CA1142014A - Photographic material containing a bleachable image dye or metallic oxide and a bleach-developer compound - Google Patents
Photographic material containing a bleachable image dye or metallic oxide and a bleach-developer compoundInfo
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- CA1142014A CA1142014A CA000315741A CA315741A CA1142014A CA 1142014 A CA1142014 A CA 1142014A CA 000315741 A CA000315741 A CA 000315741A CA 315741 A CA315741 A CA 315741A CA 1142014 A CA1142014 A CA 1142014A
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- silver halide
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- halide emulsion
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Abstract
Case 8-11402/ILF 1162/+/K
Canada Process for producing photographic images Abstract of the Disclosure A new method to produce photographic images is provided which comprises (a) imagewise exposing a photographic assembly which con-tains at least during the silver halide developing step, in order optionally a supercoat layer, at least one silver halide emulsion layer, a layer containing a modifiable image substance and a photobase, there being optionally one or more interlayers between each of said components.
(b) treating the exposed photographic assembly with an aqueous processing bath 80 as to provide in the silver halide emulsion layer or layers a solution or dispersion of an image substance modifying/silver halide developing compound (dymodev compound), thereby to develop the latent silver image in the silver halide emulsion(s), and (c) in the non-latent image areas allowing the dymodev comp compound to diffuse in a counter-imagewise manner from the silver halide emulsion layer (s) to the layer containing the modifiable image substance and there to modify reductively the image substance.
Depending on the dymodev compound and modifiable im-age substance combination closen it is possible to obtain either a negative or a positive image,
Canada Process for producing photographic images Abstract of the Disclosure A new method to produce photographic images is provided which comprises (a) imagewise exposing a photographic assembly which con-tains at least during the silver halide developing step, in order optionally a supercoat layer, at least one silver halide emulsion layer, a layer containing a modifiable image substance and a photobase, there being optionally one or more interlayers between each of said components.
(b) treating the exposed photographic assembly with an aqueous processing bath 80 as to provide in the silver halide emulsion layer or layers a solution or dispersion of an image substance modifying/silver halide developing compound (dymodev compound), thereby to develop the latent silver image in the silver halide emulsion(s), and (c) in the non-latent image areas allowing the dymodev comp compound to diffuse in a counter-imagewise manner from the silver halide emulsion layer (s) to the layer containing the modifiable image substance and there to modify reductively the image substance.
Depending on the dymodev compound and modifiable im-age substance combination closen it is possible to obtain either a negative or a positive image,
Description
THIS INVENTION relates to novel methods of processing imagewise exposed silver halide photographic material to produce photographic images and also to novel silver halide photographic material.
Ever since the advent of photography silver halide salts have been used as the photosensitive agent and for the most part developed silver has been used as the image although in colour photography final dye images have re-placed the silver image. However in a large number of photographic materials the final image is still a silver image e.g. in X-ray materials, microfilms and in graphic arts films as well as in normal black and white high speed camera films. Recently, however, the price of silver has increased to such an extent that ways have been sought in which silver halide can still be used as the photo-sensitive agent but in which a final dye image is formed even in the photographic materials listed above. By such means there can be either an almost total recovery of the silver used or at least a great reduction in the amount of silver used.
In one method of colour photography the photosensi-tive agent is a silver salt and a dye developer is used which develops the silver halide and at the same time releases a dye which diffuses out of the photosensitive layers into a receptor layer which can be peeled apart from the photosensitive layer. Thus a final dye image is obtained whilst leaving all the silver in the residual ma-terial and thus recoverable. We have discovered a novel photographic difusion process which does not involve the diffusion of dyes in the photographic material but wherein a final dye image is obtained.
Therefore according to the present invention in a process for the production of photographic images -there are provided the steps of (a) imagewise exposing a photographic assembly which com-prises in order optionally a supercoat layer, at leastone silver halide emulsion layer, a layer containing a bleachable image dye or metallic oxide and a support, there being optionally one or more interlayers between each of said components, (b) treating the exposed photographic assembly with an acid aqueous processing bath so as to provide in the silver halide emulsion layer or layers a solution or disper-sion of a bleach-developer compound, thereby to develop the latent silver irnage in the silver halide emulsion (s), and (c) in the non-latent image areas allowing the bleach-developer compound to diffuse in a counter-imagewise manner from the silver halide emulsion layer(s) to the layer containing the bleachable image dye or metallic oxide and there to reduce said dye or metallic oxide.
By "bleach-developer compound" is meant a compound which is able to develop a latent silver image and also able to reduce a bleachable dye or metallic oxide in such a way to obtain image differentiation in the image sub-stance layer which corresponds to the areas of the un-developed silver and so obtain a photographic image.
The choice of bleach-developer compound used in the process of the present invention depends on the dye or metallic oxide present in the image substance layer. If there is present a dye which can be bleached imagewise when present in a layer then the bleach-developer com pound is one which is able to bleach the image dye when the compound diffuses into the image substance layer.
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These bleach-developer compounds work in such a way -that the image dye remains in the areas of the image layer into which the bleach-developer compound has not diffused.
However in an alternative process, for example, the bleach-developer compound acts to increase the substantivity of the image substance. Thus in the areas into which -the bleach-developer compound has diffused the image dye is rendered substantive to a particular solvent. Thus on treatment with such a solvent in these areas the image dye remains whilst in the other areas the image dye is removed by the solvent. Thus depending on the bleach-developer compound and image dye combination chosen it is possible to obtain either a negative or a positive image.
The final image can also be formed by leuco dyes and other initially colourless substances which can be changed into visible image. For example a leuco dye may be present in the dye containing layer and a bleach-developer com-pound may be used such that when it diffuses into the dye containing layer it is able to alter the leuco dye to produce a visible dye therefrom. Another example of an initially colourless substance which can be converted to a coloured substance by the action of a bleach-developer compound is MoO3. When this substance is acted on by a reduced diazine (which as hereinafter stated can be used as a bleach-developer compound) the initially colourless MoO3 is converted to a coloured substance. Alternatively the bleach-developer compound may alter the leuco dye to prevent it from changing into a visible dye. A further treatm~nt step would then be required to change the leuco dye in the areas into which the bleach-developer compound has not diffused into a visible image dye.
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In this process the bleach-developer compound may be in the form of a preformed solution or dispersion which is applied to the exposed photographic assembly in step (b).
However bleach-developer compounds tend to be un-stable and thus alternative ways of treating the exposed photographic assembly to ensure that sufficient active bleach-developer compound enters the silver halide emul-sion layer(s) and especially that sufficient bleach-developer compound diffuses to the image dye layer are preferred.
Thus in one such method the bleach-developer compound is an inactive form and a solution or dispersion of this compound is contacted with a substance which renders the compound active just before or whilst the solution or dispersion is applied to the exposed photographic assembly.
In an alternative to this method the photographic assembly comprises either in the supercoat layer or below the supercoat layer but above the bottom-most silver halide layer a compound in layer form which is able to render active a solution or dispersion of an inactive bleach-developer compound. Thus in this method in step (b) a solution or dispersion of an inactive bleach-developer compound is applied to the exposed photo-graphic assembly and when the inactive compound comes into contact with the activating compound it is rendered active and thus able to develop the latent silver image.
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In a further alternative method the bleach-developer compound is present initially in a layer in the photo-graphic assembly in an inactive form and in step (b) a solvent for the compound is applied to the exposed photographic assembly and the thus formed solution of the inactive compound is treated in the assembly to convert the compound to the active form. The belach-developer compound may be treated in the assembly by providing in the assembly as well a substance in layer form which renders active the inactive bleach-developer compound. In another method at the same time or just after the solvent i5 applied in step (b) the photo-graphic assembly is subjected to electrolysis. This converts the bleach-developer compound to the active form in the assembly.
Similarly electrolysis may be used to convert a solution or dispersion of the inactive bleach-developer compound to the active form, the electrolysis being applied just before or whilst the solution or dis-persion is applied to the photographic assembly.
The term photographic assembly of the type defined as used hereinafter means a photographic assembly as defined in (a) of the two processes hereinbefore set forth, that is to say a photographic assembly which comprises at least during the development of the silver halide emulsion an optional supercoat layer, at least one silver halide emulsion layer, a layer containing a ~?
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bleachable image dye or metallic oxide and a support, there being optionally one or more interlayers between each of said layers. According to a modification there is present in this material either in the supercoat layer or in another layer above the layer containing the bleachable image dye or metallic oxide (optionally above the silver halide emulsion layer) a layer which is able to activate the non-active bleach-developer compound.
Thus in the process of the present invention when the exposed photographic assembly of the type defined is treated with an acid aqueous processing bath so as to provide in the silver halide emulsion layer or layers a solution or dispersion of the bleach-developer compound in the latent image areas of the silver halide emulsion layer(s) the bleach-developer compound develops the latent silver image and becomes oxidised and thus inactive both as a silver halide developing agent and as a bleaching agent for a bleachable image dye or metallic oxide. However in the non-latent image areas of the silver halide emulsion layer(s) the bleach-developer compound in solution or dispersion is able to diffuse through the silver halide emulsion, the compound being unaffected by the non-latent image silver halide. When the bleach-developer compound reaches the bleachable dye or metallic oxide containing layer it reduces the substance which leads to or forms a photographic iamge which preferably is of the same type as the silver image formed in the silver halide layer(s). Thus if the image formed in the silver halide emulsion layer(s) is a negative image then a negative dve image is formed in the s.
silver halide emulsion layer(s) is a direct positive image then the dye image formed in the bleachable dye layer is a direct positive image.
However as hereinbefore stated it is possible by use of suitable bleach-developer/image substance combina-tions to produce an image which is the reverse of the developed silver image.
It is to be understood that the image part of the photographic assembly as just definedl that is to say ¦ '~e portion of the assembly which includes both the layer ¦ lich comprises the bleachable image dye or metallic oxide ¦ nd the support, may be joined initially to the photosensi-¦ tive portion of the assembly that is to say the portion of the assembly which includes the silver halide emulsion layer(s) or the photosensitive portion of the assembly and the image portion of the assembly may be separate components which are brought together during processing.
If the photographic assembly comprises a separate image portion not connected initially to the photosensitive portion after the image has been formed in this portion the two components may be separated. However it is some-times preferred that after processing the two sheets are retained together.
Preferably when the photographic assembly is in two sections the supercoat layer or some other layer is such as to be able to act as a support for the silver halide emulsion layer(s) and the other layers of this section of the assembly.
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It is to be understood that the photographic assembly can and usually does include a number of layers other than the supercoat layer, the silver halide emulsion layer(s), the layer which contains the bleachable dye or metallic oxide and the optional inter layer or layers between the image dye layer and the support. For example there may be opague layers, there may he light reflecking layers, there may be timing layers which release alkali or acid or other substances as required and/or there may be mordant layers. The mordant layer~s) may be used for example to mordant released amines formed by the reduction of the bleachable image dye. Examples of assemblies of use in the present invention are shown in Figures 1 to 23 which follow. ~owever these assemblies are merely representative of the very great number of assemblies which can be used in the process of the present invention.
The term "bleachable image dye" includes preformed image dyes or the type often used in photographic material such as for example a~o dyes, anthraquinone dyes and triphenylmethane dyes. It includes also other coloured compounds such as inorganic dyes, inparticular pigments, which can provide an image and which can be reduced. For example it includes metallic oxides such as manganese dioxide and molybdenenum trioxide which can be imagewise reduced.
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_ 9 _ It îs to be understood that the term blechable image dye covers a single dye or a mixture o~ dyes of the same or different colour.
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By bleachable i~age dye is meant a dye which can be used in a silver dye bleach process for example the well-known CIBACHROME (Registered Trade Mark) silver dye bleach process.
By use of the present invention it is possible to form either a negative dye imaGe ~Ihen using a conventional silver halide emulsion or a direct positive dye image when using a direct 20sitive silver halide emulsion, prererably o~ the sur~ace ~ogged type. When using a conven~ional silver halide emulsion in the process of the present invention af~er exposure the latent silver images will be in the areas of the silver halide emulsion which have been light exposed. However when using direct positive silver halide material in the process of the present invention the latent silver images will be in the areas of the silver halide emulsion which hav~ not been li~ht~exposed.
In the conventional silver dye bleach process layer-substantive dyes are reductively destroyed in the presence of photographically developed silver. Suc~. dyes are usually azo dyes and their destruction can be represented thus:
R-N=N-Rl ~ 4H~ Ag ~ RNH2 ~ RlNH2 The custom~ry known aæo dyes 7 for e~ra~ple tho~e known from British Patent Speci~ications 923,265,999,996,1,042,300 and 1,077,628 and U.S. Patent Specifications 3,178,290, 3,178, 291, 3,183,225 and 3,211,556, can be used for carrying out the process of the invention.
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Suitable bleachable dyes are9 moreover, described for example in the Colour Index (third edition), published by the Society of Dyers and Colourists, publishers Lund Humphreys, Bradford ~nd Londorl. In addition to azo dyes it is possible, for exam~le, ~o use formazan, azoxy, xanthene, aæine, triphenylmethane, an~hraquinone, nitroso, indigo, nitro-substituted and phthalocyanine dyes, as well as other known dyes, for carrying out the process according to the invention. It is also possible to use pre-cursors o these dyes, for example hydrazo and diazonium compounds, whieh give azo dyes, and tetrazolium salts which produce forma~an-dye~. Out of the group of azo dyes which are suitable the ease with which the azo linkages can be broken depends on the nature of the substituents on the nitrogen atoms. The reduction may be a stoichiometric reaction in acid solution with the photographic silver as the reducing agent. Usually there is present a so-called dye bleach catalyst for example certain diazine compounds which form reversible redox systems. These compounds are reduced at the surface of the exposed silver and their reduction products diffuse to the dye and bleach it.
Examples of suitable bleachable image dyes of the azo type are:
Yellow SO3H OCH3 ,CH3 SO3H
N=N ~ - NHCO ~ CONH- ~ -N=N ~
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Magenta:
SO H
OH
N=N- ~ -NHCO- ~ -NHCONH- ~ -CONH- ~3 -N=N-NH2 S03H . S03H H N
OH /CH3 . C\3 HO-N-N- ~ -NHCO- ~ -CONH- ~ - N -N
NH S03H S03H N}I
CH ~ CH3 CH3` ~ CH3 j, . . .
- - ,. .
NH2 ` H2N
~-N = N-~-NH - CO - NH -~ -N = N- ~) H~--OH HO3S SO3H HO-St)3H
Cyan:
CO-NH OH OCH3 OEI NHCO_ ~ Cl ~ N= N - ~ - N=N ~
SO NH OH _ OCE13 OH NElSO
3 503H ~ ~03S ~ S203H
-CO-NH OH
~-~ ~ N = N- ~ N--N
S03~
By bleach developer compound is meant a compound which is able both to develop a latent silver halide image and to bleach a bleachable image dye or metallic oxide.
Various classes of bleach developer compounds are known.
Perhaps the best known class is the reduced form of silver dy bleach catalysts. Silver dye bleach catalysts are used in the silver dye bleach process in which they accelerate greatly the silver dye bleach process to bleach the dye in accord with the developed silver areas. Silver dye bleach catalysts work in an acid solution. The most widely used dye bleach catalysts are diazine compounds, especially 1,4 diazines, for example pyrazines, quinoxa-lines and phenazines in their reduced form.
Examples of suitable diazines are pyrazine and i-ts derivatives and quinoxaline compounds~ especially those which are substituted in the 2-, 3-, 5-, 6- and/or 7-position by lower alkyl, hydroxyalkyl or alkoxy (Cl-C4), especially methyl, hydroxymethyl or methoxy, further by acylated hydroxymethyl groups ~CH2 - S03H), amino or acyla-ted (acetylated~ amino groups, carboxyl, sulfonic acid (S03H), benzoyl, acetyl, phenyl, benzyl or pyridyl.
The l,~-diazine compounds are preerably used in the ~orm of aqueous solutions. The solution can also contain a mixture of two or more diazines.
- The diazines can be present in the photographic assembly in suspension or as a solution in a high-boiling solvent. Furthermore, the diazines can be incorporated in capsules in the photographic assembly which can be broken by a change in pressure, temperaturè or pH, in the light-sensitive layer or in an adjacent layer.
Usable dye bleach catalysts are also described in German Auslegeschriften 2 010,707~ 2,144,298 and 2,144,297, in French Patent Specification 1,489,460 and in U.S. Patent Specification 2,270,118.
I~ is known from B.P. 1,183,176 that ~;he reduced form of such diazine compounds can act as silver halide develop ing agents.
Another particularly useful class of bleach developer compounds are salts of metallic ions and complexes of metallic ions with suitable ligands which are capable of acting as silver halide developing agents.
Metallic ions which are capable of acting as developing agents for latent silver images arè well known (see for example Photographi~ Processing Chemistry by L.F'.A. Mason, Focal Press 2nd Edition 1975 pages 177-180). Such metallic ions are the lower valency state ions of variable valency metals. In general they act at low pH's to pre~
serve their active lower valency state.
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We have discovered that metallic ions and complexes of metallic ions with suitable ligands which are capable of acting as developing agents for latent silver images in an aqueous acid solution are able also to act in an acid so-lution as bleaching agents for bleachable dyes or metallic oxides. However they are not silver dye bleach catalysts because after bleaching the bleachable dye or metallic oxide they become oxidised to their higher valency state but can not be reduced to their lower valency state by metallic silver as are silver dye bleach catalysts.
Preferred metallic ions for use as silver halide developing agents in the process of the present invention are chromous that is to say Cr , vanadous that is to say V and titanous that is to say Ti There may be present also in the bleach-developer so-lution which comprises such metal ions a ligand e.g.
ethylene diamine tetraacetic acid which beneficially modifies the redox potential of the metal ions.
The preferred bleach-developer compounds of use in the present invention, that is to say the reduced dye bleach catalysts and the lower valency ions of metallic salts or complexes as hereinbefore defined, both act in an aqueous acid solution.
The photographic assembly of the type defined may as previously described consist of two components one the image portion and the other the photosensitive portion.
After exposure of the silver halide emulsion layer(s) processing liquid is introduced between them or coated on one of the portions and the two portions are brought together in close contact.
When an assembly of this type is used to perform the invention the processing fluid may con-tain a pre-formed bleach-developer compound or an inactive form thereof which is not able to act either as silver halide developing agent nor as dye bleaching agent. In the second case when an inactive bleach-developer compound is used there may be present in the photosensitive portion of the assembly preferably between the supercoat layer and the silver halide emulsion layer(s) a metallic layer as hereinafter described. When the processing fluid is introduced between the image portion and the photosensitive portion the bleach-developer compound diffuses into this metallic layer and there is reduced to its active state. It then diffuses into the silver halide emulsion layer(s) and there the latent image areas of the silver halide are developed by the compound but in the non-latent image areas the compound diffuses into the image portion there bleaching the dye or metallic oxide to form a dye image. Thereafter the image portion containing the dye image may be removed from contact with the photosensitive portion of the assembly. If a preformed bleach-developer compound is used in a two-component assembly preferably the supercoat layer comprises one component and the photosensitive portion and image portion are both coated on the support and comprise the second component. After exposure of the assembly processing fluid containing the preformed bleach-developer is introduced between the supercoat layer and the emulsion layer. The supercoat layer can be separated from the second component after processing.
However sometimes it is preferable that after process-ing the two portions of the assembly are not separated but are caused to adhere toyether. This avoids the production of a disposable photosensitive portion of the assembly.
The formation of the photographic assembly in two halves is of particular use when in-camera processing is to be carried out. In this case in the photographic assembly the photosensitive portion and the image portion may be in contact but no* ~oined. After exposure of the silver halide emulsion layer(s) the processing liquid can be introduced between the two portions, possibly by intro-ducing a pod between the two portions, rupturing the pod and causing the liquid to spread between the two portions which are held in close contact.
However when the photographic assembly is initially in one piece there may be a stripping layer or a stripping position. This layer or position is between the silver halide emulsion layer~s) and the image dye layer. When there is such a stripping layer or stripping position sometimes a final step in the process of the present in-vention is required to activate the stripping effect and to separate the portion of the photographic assembly which comprises the developed silver image from the portion which contains the final dye image on the support.
If there is a stripping layer this may be dissolved in a final wash or solution bath. An example of a suitable stripping layer is a phthalated gelatin layer which is , ~ ~ ~
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swellable in water. However usually the stripping effect takes place during the processing, because, for example, phthalated gelatin is swellable in an acid processing solution.
Alternatively there may be a stripping position, that is to say the interface between two layers is such that adhesion failure between the two layers can be caused.
This adhesion failure may be caused, for example, by change of pH or temperature. The stripping position should be between the silver halide emulsion layer(s) and the image layer which contains the bleachable dye or metallic oxide so that the final s-tep in the process may be to activate the adhesion failure so separating the photosensitive portion from the image portion. However it is usual for adhesion failure to occur towards the end of processing so that often no actual step to activate stripping is required.
When the photographic assembly is initially in two portions or there is either a stripping layer or stripping position in ~he photographic assembly as hereinbefore defined all the silver used as the photosensitive agent can be recovered as the portion of the material containing the silver may be separated from the final image portion.
However there is considerable saving in silver even when the image portion is not separated from the portion containing the silver. In this case the final viewable image is the dye image which is viewed through the trans-.~
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parent support there being also a silver image in the photographic material which is likely to be ~eparated from the dye image by a white opaque layer. In such material ..... . . . . . ..... ..
the amount of silver halide present in the silver halide emulsion layer can be ~ess than that which would be required if a viewable image were to be formed in the silver halide emulsion layer(s).
The solution of bleach-developer compound Or use in the preferred process of the present invention may be pre-pared and applied to the photographic assembly in a number of different ways.
For example if the bleach-developer compound used is a reduced diazine compound, this compound may be applied to the photographic assembly as a preformed reduced compound.
The methods of forming a reduced derivative of 1,4-diazine compound are described in British Patent Specification No.
1183176.
Alterr.atively, and this is preferred, the reduced diazine compound is produced during the processing step from a diazine compound or from a N-oxide derived therefrom by use Or a reducing agent in iayer form in an acid medium, the said reducing agent being a metal which in the electro-chemical series of the elements is above silver and up to and including aluminium. This method of processing is described in B.P. Spec;fication No. 1330755.
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For the present invention the reducing agents can be metals, which are in the electrochemical series above silver and up to and including lanthanum, preferably up to and includïng aluminium, such metals are e.g.: copper iron, lead, tin, nickel, cobalt, indium gallium, cadmium, manganese, aluminium and lanthanum. Further alloys con-taining these metals or said metals in amalgamated form can be used.
For example there may be used a vacuum deposited coated metal strip for example a tin or copper film base strip and there is coated on to this coated strip or on the exposed photographic material a solution or paste which comprises a 1,4-diazine compound in an acid solution. The diazine compound is reduced by the metal and diffuses into the photographic material where the reduced diazine compound in the presence of the acid solution acts as a developing agent for the exposed silver halide.
Alternatively there may be present in the photographic material a layer which contains a fine or colloidal dis-persion of a metal which in the electrochemical series is above silver and up to and including aluminium. In fact a colloidal dispersion of aluminium is particularly useful.
In a further alternative method the reduced diazine compounds may be formed in the assembly during the development step by electrolysis.
Similarly if the bleach-developer compound comprises simple or complexed metallic ions in a reduced state these ions may be prepared and applied to the photographic assembly , Z~
in a number of dif~erent ways.
For example al~a preformed acid solution o~ the metallic ions may be used~ bl)the acid solution of the metallic ions may be formed externally to the photographic assembly but as a step in the processing sequence, cl)the acid solution of the simple or complexed reduced metallic ions may be formed in situ in the photographic assembly during the processin~ sequence.
Thus in the method ~) above the reduced metal ion may be preformed by known methods, such as electrolytic reduction of a suitable oxidised form or ~ormation of the required metal ion complex by admixture of suitable starting materials ;in the required oxidation state.
When method bl~is used a ~rip (foi~o a second metal or a strip having a fine colloid dispersion of a second metal coated thereon is used: the second metal having a reduction potential sufflciently negat;ve to achieve reduction of the oxidised form of the metallic ion to the reduced rorm of ,~. . .
the metallic ion. The metal strips are e.g. composed of aluminium, iron, ~inc or tin; ~urther of indium or alloys which include such metals. When employed in a ~ine colloid dispersion the metals are for example zinc, tin, iron~
nickel, aluminium or indium may be used; fu~tller gallium lanthanum, or alloys containing these metals.
There is coated on to this coated strip which is then applied to the exposed photographic assembly a solution or paste which comprises an oxidised form Or the metalli~ ion in acid solution. The oxidised form Or the metallic ion is reduced by the second metal and diffuses into the photo-graphic assembly where the reduced form of the metallic ion in the presence of the acid solution acts as a developing agent for the latent silver halide. In case cl)there may be present in the photographic assembly a layer ~hich con-tains a fine or colloid dispersion of a second metal which can reduce oxidised forms of ~he metallic ions to produce the active form of the ions. Such metals are alumin-ium, copper~zinc, tin,iron, nickel, gallium or indium, further lanthanum or alloys which include such metals. Also in ~e~hod cl) the reduced metallic ions may be formed electrolyti-cally in the assembly during the silver halide developing step.
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Preferred metals amongst these are those which do not react rapidly with atmospheric oxygen and water at room temperature.
If desired, complex-forming agents for the metals can also be employed during processing.
For example, ~he fluoride ion forms complexes with aluminium-III ions and the copper-I ion is bonded as a complex by, for example, nitriles, olefines, chloride ions, bromide ions and thioethers. ~A large number of ligands and also the stability constants of the complexes formed therefrom with various metal ions are listed in the book "Stability Constants of Metal-Ion Complexes, Special Publi-cation No. 17, London: The Chemical Society~ Burlington House, W.l., 1964". During processing, a complex-bonded metal ion forms from the complex-formirlg agent (for example fluoride ions from ~H4~ or CaF2 for Al), incorporated in the processing solution or in the material, and the metal, which is present ir, the form of a layer in the photographic material or is brought into contact with the photographic material during processing, with interposition of the pro-cessing bath, and by this means an increase ln the reactivity of the metal is achieved.
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The use of sparingly soluble compounds as donors of complex-forming agents, for example CaF2 as a fluoride ion donor, has the advantage that an adequate amount of ligand for forming the complex is available without, at the same time, a momentarily undesirable high excess of ligand being present in the solution.
The metals can be distributed in the form of small particles in a layer containing a silver salt or in an adjacent auxiliary layer which may be present. Auxiliary layers can be bonded to the silver salt emulsion layer in an inseparable or readily separable manner. The particles can be dispersed direct in a layer colloid or can addition-ally be surrounded by a coating`of a polymeric substance.
Furthermore, the metal particlès can be contained in cap-sules which can be broken open by a change in pressure, temperature or pH. In addition the metals can be supplied for use from small particles of a polymeric substance pro-vided with a metallic coating.
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- z3 -Various embodiments of photographic assemblies of use in the present invention will now be described with refer-ences-to the accompanying figures 1 to 23.
Figures 1 to 13 show assemblies which comprise either a stripping position or stripping layer.
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Figures 14 to 19 show integral assemblies.
Figures 20 to 22 show assemblies which comprise a photosensitive portion and an image portion which are only brought together during processing.
Figure 23 shows an assembly in two sections suitable for in-camera processing.
In figures 1 to 13 the term stripping position has been used, however this may be either an ir.terface between layers at which adhesion failure may occur or it may indi-cate an actual stripping layer.
In figure 1 there is shown a photographic material according to the present invention which can be used for X-ray film material.
As shown in figure 1 the material comprises a trans-parent support l having coated thereon a bleachable dye-in-gelatin layer 2. Abovè this is the stripping position 3. Above the stripping position 3 is a carbon black layer 4 and above this a conventional silver halide emulsion layer 5, then a carbon black layer 6 and above is a supercoat layer 7. Thus the silver halide emulsion layer 5 is sandwiched between two carbon black layers ll - ~4 -and 6 and therefore the photographic material can be handled in daylight. The material may be exposed to X-rays and a~ter exposure it can bè processed using an aqueous acid solution of the bleach-developer compound as just described to yield a negative silver image. The silver halide layer and the two carbon black layers and ~the supercoat layer are then stripped off ~he dye layer for recovery~of the silver. The negative dye image on the support can ~hen be viewed by transmission.
For convenience the expression "X-ray" as used in the speci~ication is intended to cover all very short wave photographically useful radioactive rays such as those émanating from an X-ray tube, radium or radioact;ve iso-topes.
In figure 2 there is shown photographic material according to the present invention which can be used as X-ray material for reflection viewing. In this embodiment there is coated on a transparent film support 1 in order a bleachable dye-in-gelatin layer 2, a white opaque layer 3, stripping position 4, a carbon black layer r, a conventional silver halide emulsion layer 6,~ a carbon black layer 7 and a supercoat layer 8.
In this case as in the case of the material o~ figure l the photographic material is processed to yield a negative image. But in this material an extra white opaque layer is present. This may consist f'or example Or baryta or - ~
Z~
titanium oxide dispersed in gelatin. In this rnaterial the whike opaque layer acts as a reflective base ~or the negative dye image which is viewed by reflection through the film support.
, . .
Figure 3 shows an alternative embodiment of the material of figure 2. In this figure the layers have the same numbers as in figure 2 but the stripping position has now been altered and is between the lower carbon b~ack layer 5 and the silver halide emulsion layer 6. When the silver halide emulsion layer is stripped off after process-ing the carbon black layer is then attached to the white opaque layer.
The main advantages of the photographic material as described with references to rigures 1 to 3 is that all silver in the silver halide emulsion layer may be recovered and the film material is insensitive to daylight and thus may be handled in the unexposed state in normal daylight conditions. However the photographic material of the present invention can also be used in a norr.;al camera or process camera if the top carbon black layer is omitted.
Such material in which there is no carbon black layer at all is shown in the accompanying figure 4 in which there is coated on an opaque ~upport 1 in order a bleachable dye-in-gelatin layer 2, stripping posit;on 3, a silver halide emulsion layer 4 and a supercoat layer 5. Prerer-ably this material comprises in layer 4 a direct positive emulsion and thus l~hen processed yields a d rect positive dye image which is viewed by reflection. In this case the material cannot be handled at any stage in daylight conditions before the silver halide layer has been stripped of~.
Yet another embodiment of the material of the present invention .s shown in the accompanying figure 5. In this material there is coated on a transparent support 1 i~
order a bl~achable dye-in-gelatin layer 2, stripping posi-tion 3, carbon black layer 4, silver halide emulsion layer .~ .
5 and supercoat layer 6. In this case the material pro-duces a final dye image which may be viewed by transmission.
In the case of this material exposure must be in a camera or other light-tight exposure chamber. However if the material is processed by a method wherein an activator metal foil which is light opaque is placed in contact ~ith the photographic material on the supercoat side then the processing may be carried out under daylight conditions.
Another embodiment of the invention is shown in figure 6 in which there is coated on ~a transparent support 1``
in order a bleachable dye-in-gelatin layer 2, white opaque layer ~, carbon black layer 4, stripping position 5, silver halide layer 6 and supercoat layer 7. In this case also, exposure must be in a camera or light-tight exposure chamber.
The silver halide emulsion layer 6 may be a direct positive emulsion and in which case after processing there is pro-duced a direct positive image which is viewed by reflection.
.. . . .. . ... .. .....
Alternatively if a conventional silver halide emulsion is used there is produced a nega~ive image which is viewed by reflection, although of course it would be more usual in this case to employ material which would produce a direct positive image as the image is viewed by reflection unless exposure were to X-rays when it is usual to view negative images.
The assemblies shown in Figures 1 to 6 may be processed by the application of an acid solution which comprises a bleach-developer compound. This bleach-developer compound may be a preformed reduced azine for example the dihydro derivative of methyl acetyl quinoxaline which remains as the active compound for some time especially if kept under a nitrogen atmosphere. However bleach-developer compounds which comprise an aqueous acid solution of metallic ions in their lower valency state are especially suitable, e.g.
titanous ions stabilised with ethylene diamine tetraacetic acid. Such solutions remain active for some time. Altern-atively as men~ioned with reference to figure 5 the inactive bleach-developer solution can be used together with an activator metal foil e.g. aluminium or zinc foil, ~he metal reducing the inactive bleach-developer to the active form as it contacts the photographic assembly.
Such methods Or processing are shown in ~igures 7 and
Ever since the advent of photography silver halide salts have been used as the photosensitive agent and for the most part developed silver has been used as the image although in colour photography final dye images have re-placed the silver image. However in a large number of photographic materials the final image is still a silver image e.g. in X-ray materials, microfilms and in graphic arts films as well as in normal black and white high speed camera films. Recently, however, the price of silver has increased to such an extent that ways have been sought in which silver halide can still be used as the photo-sensitive agent but in which a final dye image is formed even in the photographic materials listed above. By such means there can be either an almost total recovery of the silver used or at least a great reduction in the amount of silver used.
In one method of colour photography the photosensi-tive agent is a silver salt and a dye developer is used which develops the silver halide and at the same time releases a dye which diffuses out of the photosensitive layers into a receptor layer which can be peeled apart from the photosensitive layer. Thus a final dye image is obtained whilst leaving all the silver in the residual ma-terial and thus recoverable. We have discovered a novel photographic difusion process which does not involve the diffusion of dyes in the photographic material but wherein a final dye image is obtained.
Therefore according to the present invention in a process for the production of photographic images -there are provided the steps of (a) imagewise exposing a photographic assembly which com-prises in order optionally a supercoat layer, at leastone silver halide emulsion layer, a layer containing a bleachable image dye or metallic oxide and a support, there being optionally one or more interlayers between each of said components, (b) treating the exposed photographic assembly with an acid aqueous processing bath so as to provide in the silver halide emulsion layer or layers a solution or disper-sion of a bleach-developer compound, thereby to develop the latent silver irnage in the silver halide emulsion (s), and (c) in the non-latent image areas allowing the bleach-developer compound to diffuse in a counter-imagewise manner from the silver halide emulsion layer(s) to the layer containing the bleachable image dye or metallic oxide and there to reduce said dye or metallic oxide.
By "bleach-developer compound" is meant a compound which is able to develop a latent silver image and also able to reduce a bleachable dye or metallic oxide in such a way to obtain image differentiation in the image sub-stance layer which corresponds to the areas of the un-developed silver and so obtain a photographic image.
The choice of bleach-developer compound used in the process of the present invention depends on the dye or metallic oxide present in the image substance layer. If there is present a dye which can be bleached imagewise when present in a layer then the bleach-developer com pound is one which is able to bleach the image dye when the compound diffuses into the image substance layer.
B
These bleach-developer compounds work in such a way -that the image dye remains in the areas of the image layer into which the bleach-developer compound has not diffused.
However in an alternative process, for example, the bleach-developer compound acts to increase the substantivity of the image substance. Thus in the areas into which -the bleach-developer compound has diffused the image dye is rendered substantive to a particular solvent. Thus on treatment with such a solvent in these areas the image dye remains whilst in the other areas the image dye is removed by the solvent. Thus depending on the bleach-developer compound and image dye combination chosen it is possible to obtain either a negative or a positive image.
The final image can also be formed by leuco dyes and other initially colourless substances which can be changed into visible image. For example a leuco dye may be present in the dye containing layer and a bleach-developer com-pound may be used such that when it diffuses into the dye containing layer it is able to alter the leuco dye to produce a visible dye therefrom. Another example of an initially colourless substance which can be converted to a coloured substance by the action of a bleach-developer compound is MoO3. When this substance is acted on by a reduced diazine (which as hereinafter stated can be used as a bleach-developer compound) the initially colourless MoO3 is converted to a coloured substance. Alternatively the bleach-developer compound may alter the leuco dye to prevent it from changing into a visible dye. A further treatm~nt step would then be required to change the leuco dye in the areas into which the bleach-developer compound has not diffused into a visible image dye.
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In this process the bleach-developer compound may be in the form of a preformed solution or dispersion which is applied to the exposed photographic assembly in step (b).
However bleach-developer compounds tend to be un-stable and thus alternative ways of treating the exposed photographic assembly to ensure that sufficient active bleach-developer compound enters the silver halide emul-sion layer(s) and especially that sufficient bleach-developer compound diffuses to the image dye layer are preferred.
Thus in one such method the bleach-developer compound is an inactive form and a solution or dispersion of this compound is contacted with a substance which renders the compound active just before or whilst the solution or dispersion is applied to the exposed photographic assembly.
In an alternative to this method the photographic assembly comprises either in the supercoat layer or below the supercoat layer but above the bottom-most silver halide layer a compound in layer form which is able to render active a solution or dispersion of an inactive bleach-developer compound. Thus in this method in step (b) a solution or dispersion of an inactive bleach-developer compound is applied to the exposed photo-graphic assembly and when the inactive compound comes into contact with the activating compound it is rendered active and thus able to develop the latent silver image.
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-- 5 ~
In a further alternative method the bleach-developer compound is present initially in a layer in the photo-graphic assembly in an inactive form and in step (b) a solvent for the compound is applied to the exposed photographic assembly and the thus formed solution of the inactive compound is treated in the assembly to convert the compound to the active form. The belach-developer compound may be treated in the assembly by providing in the assembly as well a substance in layer form which renders active the inactive bleach-developer compound. In another method at the same time or just after the solvent i5 applied in step (b) the photo-graphic assembly is subjected to electrolysis. This converts the bleach-developer compound to the active form in the assembly.
Similarly electrolysis may be used to convert a solution or dispersion of the inactive bleach-developer compound to the active form, the electrolysis being applied just before or whilst the solution or dis-persion is applied to the photographic assembly.
The term photographic assembly of the type defined as used hereinafter means a photographic assembly as defined in (a) of the two processes hereinbefore set forth, that is to say a photographic assembly which comprises at least during the development of the silver halide emulsion an optional supercoat layer, at least one silver halide emulsion layer, a layer containing a ~?
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bleachable image dye or metallic oxide and a support, there being optionally one or more interlayers between each of said layers. According to a modification there is present in this material either in the supercoat layer or in another layer above the layer containing the bleachable image dye or metallic oxide (optionally above the silver halide emulsion layer) a layer which is able to activate the non-active bleach-developer compound.
Thus in the process of the present invention when the exposed photographic assembly of the type defined is treated with an acid aqueous processing bath so as to provide in the silver halide emulsion layer or layers a solution or dispersion of the bleach-developer compound in the latent image areas of the silver halide emulsion layer(s) the bleach-developer compound develops the latent silver image and becomes oxidised and thus inactive both as a silver halide developing agent and as a bleaching agent for a bleachable image dye or metallic oxide. However in the non-latent image areas of the silver halide emulsion layer(s) the bleach-developer compound in solution or dispersion is able to diffuse through the silver halide emulsion, the compound being unaffected by the non-latent image silver halide. When the bleach-developer compound reaches the bleachable dye or metallic oxide containing layer it reduces the substance which leads to or forms a photographic iamge which preferably is of the same type as the silver image formed in the silver halide layer(s). Thus if the image formed in the silver halide emulsion layer(s) is a negative image then a negative dve image is formed in the s.
silver halide emulsion layer(s) is a direct positive image then the dye image formed in the bleachable dye layer is a direct positive image.
However as hereinbefore stated it is possible by use of suitable bleach-developer/image substance combina-tions to produce an image which is the reverse of the developed silver image.
It is to be understood that the image part of the photographic assembly as just definedl that is to say ¦ '~e portion of the assembly which includes both the layer ¦ lich comprises the bleachable image dye or metallic oxide ¦ nd the support, may be joined initially to the photosensi-¦ tive portion of the assembly that is to say the portion of the assembly which includes the silver halide emulsion layer(s) or the photosensitive portion of the assembly and the image portion of the assembly may be separate components which are brought together during processing.
If the photographic assembly comprises a separate image portion not connected initially to the photosensitive portion after the image has been formed in this portion the two components may be separated. However it is some-times preferred that after processing the two sheets are retained together.
Preferably when the photographic assembly is in two sections the supercoat layer or some other layer is such as to be able to act as a support for the silver halide emulsion layer(s) and the other layers of this section of the assembly.
~2~
It is to be understood that the photographic assembly can and usually does include a number of layers other than the supercoat layer, the silver halide emulsion layer(s), the layer which contains the bleachable dye or metallic oxide and the optional inter layer or layers between the image dye layer and the support. For example there may be opague layers, there may he light reflecking layers, there may be timing layers which release alkali or acid or other substances as required and/or there may be mordant layers. The mordant layer~s) may be used for example to mordant released amines formed by the reduction of the bleachable image dye. Examples of assemblies of use in the present invention are shown in Figures 1 to 23 which follow. ~owever these assemblies are merely representative of the very great number of assemblies which can be used in the process of the present invention.
The term "bleachable image dye" includes preformed image dyes or the type often used in photographic material such as for example a~o dyes, anthraquinone dyes and triphenylmethane dyes. It includes also other coloured compounds such as inorganic dyes, inparticular pigments, which can provide an image and which can be reduced. For example it includes metallic oxides such as manganese dioxide and molybdenenum trioxide which can be imagewise reduced.
, , .
_ 9 _ It îs to be understood that the term blechable image dye covers a single dye or a mixture o~ dyes of the same or different colour.
, . ., ,~, . . .
By bleachable i~age dye is meant a dye which can be used in a silver dye bleach process for example the well-known CIBACHROME (Registered Trade Mark) silver dye bleach process.
By use of the present invention it is possible to form either a negative dye imaGe ~Ihen using a conventional silver halide emulsion or a direct positive dye image when using a direct 20sitive silver halide emulsion, prererably o~ the sur~ace ~ogged type. When using a conven~ional silver halide emulsion in the process of the present invention af~er exposure the latent silver images will be in the areas of the silver halide emulsion which have been light exposed. However when using direct positive silver halide material in the process of the present invention the latent silver images will be in the areas of the silver halide emulsion which hav~ not been li~ht~exposed.
In the conventional silver dye bleach process layer-substantive dyes are reductively destroyed in the presence of photographically developed silver. Suc~. dyes are usually azo dyes and their destruction can be represented thus:
R-N=N-Rl ~ 4H~ Ag ~ RNH2 ~ RlNH2 The custom~ry known aæo dyes 7 for e~ra~ple tho~e known from British Patent Speci~ications 923,265,999,996,1,042,300 and 1,077,628 and U.S. Patent Specifications 3,178,290, 3,178, 291, 3,183,225 and 3,211,556, can be used for carrying out the process of the invention.
. ... .. . ...
Suitable bleachable dyes are9 moreover, described for example in the Colour Index (third edition), published by the Society of Dyers and Colourists, publishers Lund Humphreys, Bradford ~nd Londorl. In addition to azo dyes it is possible, for exam~le, ~o use formazan, azoxy, xanthene, aæine, triphenylmethane, an~hraquinone, nitroso, indigo, nitro-substituted and phthalocyanine dyes, as well as other known dyes, for carrying out the process according to the invention. It is also possible to use pre-cursors o these dyes, for example hydrazo and diazonium compounds, whieh give azo dyes, and tetrazolium salts which produce forma~an-dye~. Out of the group of azo dyes which are suitable the ease with which the azo linkages can be broken depends on the nature of the substituents on the nitrogen atoms. The reduction may be a stoichiometric reaction in acid solution with the photographic silver as the reducing agent. Usually there is present a so-called dye bleach catalyst for example certain diazine compounds which form reversible redox systems. These compounds are reduced at the surface of the exposed silver and their reduction products diffuse to the dye and bleach it.
Examples of suitable bleachable image dyes of the azo type are:
Yellow SO3H OCH3 ,CH3 SO3H
N=N ~ - NHCO ~ CONH- ~ -N=N ~
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Magenta:
SO H
OH
N=N- ~ -NHCO- ~ -NHCONH- ~ -CONH- ~3 -N=N-NH2 S03H . S03H H N
OH /CH3 . C\3 HO-N-N- ~ -NHCO- ~ -CONH- ~ - N -N
NH S03H S03H N}I
CH ~ CH3 CH3` ~ CH3 j, . . .
- - ,. .
NH2 ` H2N
~-N = N-~-NH - CO - NH -~ -N = N- ~) H~--OH HO3S SO3H HO-St)3H
Cyan:
CO-NH OH OCH3 OEI NHCO_ ~ Cl ~ N= N - ~ - N=N ~
SO NH OH _ OCE13 OH NElSO
3 503H ~ ~03S ~ S203H
-CO-NH OH
~-~ ~ N = N- ~ N--N
S03~
By bleach developer compound is meant a compound which is able both to develop a latent silver halide image and to bleach a bleachable image dye or metallic oxide.
Various classes of bleach developer compounds are known.
Perhaps the best known class is the reduced form of silver dy bleach catalysts. Silver dye bleach catalysts are used in the silver dye bleach process in which they accelerate greatly the silver dye bleach process to bleach the dye in accord with the developed silver areas. Silver dye bleach catalysts work in an acid solution. The most widely used dye bleach catalysts are diazine compounds, especially 1,4 diazines, for example pyrazines, quinoxa-lines and phenazines in their reduced form.
Examples of suitable diazines are pyrazine and i-ts derivatives and quinoxaline compounds~ especially those which are substituted in the 2-, 3-, 5-, 6- and/or 7-position by lower alkyl, hydroxyalkyl or alkoxy (Cl-C4), especially methyl, hydroxymethyl or methoxy, further by acylated hydroxymethyl groups ~CH2 - S03H), amino or acyla-ted (acetylated~ amino groups, carboxyl, sulfonic acid (S03H), benzoyl, acetyl, phenyl, benzyl or pyridyl.
The l,~-diazine compounds are preerably used in the ~orm of aqueous solutions. The solution can also contain a mixture of two or more diazines.
- The diazines can be present in the photographic assembly in suspension or as a solution in a high-boiling solvent. Furthermore, the diazines can be incorporated in capsules in the photographic assembly which can be broken by a change in pressure, temperaturè or pH, in the light-sensitive layer or in an adjacent layer.
Usable dye bleach catalysts are also described in German Auslegeschriften 2 010,707~ 2,144,298 and 2,144,297, in French Patent Specification 1,489,460 and in U.S. Patent Specification 2,270,118.
I~ is known from B.P. 1,183,176 that ~;he reduced form of such diazine compounds can act as silver halide develop ing agents.
Another particularly useful class of bleach developer compounds are salts of metallic ions and complexes of metallic ions with suitable ligands which are capable of acting as silver halide developing agents.
Metallic ions which are capable of acting as developing agents for latent silver images arè well known (see for example Photographi~ Processing Chemistry by L.F'.A. Mason, Focal Press 2nd Edition 1975 pages 177-180). Such metallic ions are the lower valency state ions of variable valency metals. In general they act at low pH's to pre~
serve their active lower valency state.
~f~
We have discovered that metallic ions and complexes of metallic ions with suitable ligands which are capable of acting as developing agents for latent silver images in an aqueous acid solution are able also to act in an acid so-lution as bleaching agents for bleachable dyes or metallic oxides. However they are not silver dye bleach catalysts because after bleaching the bleachable dye or metallic oxide they become oxidised to their higher valency state but can not be reduced to their lower valency state by metallic silver as are silver dye bleach catalysts.
Preferred metallic ions for use as silver halide developing agents in the process of the present invention are chromous that is to say Cr , vanadous that is to say V and titanous that is to say Ti There may be present also in the bleach-developer so-lution which comprises such metal ions a ligand e.g.
ethylene diamine tetraacetic acid which beneficially modifies the redox potential of the metal ions.
The preferred bleach-developer compounds of use in the present invention, that is to say the reduced dye bleach catalysts and the lower valency ions of metallic salts or complexes as hereinbefore defined, both act in an aqueous acid solution.
The photographic assembly of the type defined may as previously described consist of two components one the image portion and the other the photosensitive portion.
After exposure of the silver halide emulsion layer(s) processing liquid is introduced between them or coated on one of the portions and the two portions are brought together in close contact.
When an assembly of this type is used to perform the invention the processing fluid may con-tain a pre-formed bleach-developer compound or an inactive form thereof which is not able to act either as silver halide developing agent nor as dye bleaching agent. In the second case when an inactive bleach-developer compound is used there may be present in the photosensitive portion of the assembly preferably between the supercoat layer and the silver halide emulsion layer(s) a metallic layer as hereinafter described. When the processing fluid is introduced between the image portion and the photosensitive portion the bleach-developer compound diffuses into this metallic layer and there is reduced to its active state. It then diffuses into the silver halide emulsion layer(s) and there the latent image areas of the silver halide are developed by the compound but in the non-latent image areas the compound diffuses into the image portion there bleaching the dye or metallic oxide to form a dye image. Thereafter the image portion containing the dye image may be removed from contact with the photosensitive portion of the assembly. If a preformed bleach-developer compound is used in a two-component assembly preferably the supercoat layer comprises one component and the photosensitive portion and image portion are both coated on the support and comprise the second component. After exposure of the assembly processing fluid containing the preformed bleach-developer is introduced between the supercoat layer and the emulsion layer. The supercoat layer can be separated from the second component after processing.
However sometimes it is preferable that after process-ing the two portions of the assembly are not separated but are caused to adhere toyether. This avoids the production of a disposable photosensitive portion of the assembly.
The formation of the photographic assembly in two halves is of particular use when in-camera processing is to be carried out. In this case in the photographic assembly the photosensitive portion and the image portion may be in contact but no* ~oined. After exposure of the silver halide emulsion layer(s) the processing liquid can be introduced between the two portions, possibly by intro-ducing a pod between the two portions, rupturing the pod and causing the liquid to spread between the two portions which are held in close contact.
However when the photographic assembly is initially in one piece there may be a stripping layer or a stripping position. This layer or position is between the silver halide emulsion layer~s) and the image dye layer. When there is such a stripping layer or stripping position sometimes a final step in the process of the present in-vention is required to activate the stripping effect and to separate the portion of the photographic assembly which comprises the developed silver image from the portion which contains the final dye image on the support.
If there is a stripping layer this may be dissolved in a final wash or solution bath. An example of a suitable stripping layer is a phthalated gelatin layer which is , ~ ~ ~
,~
swellable in water. However usually the stripping effect takes place during the processing, because, for example, phthalated gelatin is swellable in an acid processing solution.
Alternatively there may be a stripping position, that is to say the interface between two layers is such that adhesion failure between the two layers can be caused.
This adhesion failure may be caused, for example, by change of pH or temperature. The stripping position should be between the silver halide emulsion layer(s) and the image layer which contains the bleachable dye or metallic oxide so that the final s-tep in the process may be to activate the adhesion failure so separating the photosensitive portion from the image portion. However it is usual for adhesion failure to occur towards the end of processing so that often no actual step to activate stripping is required.
When the photographic assembly is initially in two portions or there is either a stripping layer or stripping position in ~he photographic assembly as hereinbefore defined all the silver used as the photosensitive agent can be recovered as the portion of the material containing the silver may be separated from the final image portion.
However there is considerable saving in silver even when the image portion is not separated from the portion containing the silver. In this case the final viewable image is the dye image which is viewed through the trans-.~
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parent support there being also a silver image in the photographic material which is likely to be ~eparated from the dye image by a white opaque layer. In such material ..... . . . . . ..... ..
the amount of silver halide present in the silver halide emulsion layer can be ~ess than that which would be required if a viewable image were to be formed in the silver halide emulsion layer(s).
The solution of bleach-developer compound Or use in the preferred process of the present invention may be pre-pared and applied to the photographic assembly in a number of different ways.
For example if the bleach-developer compound used is a reduced diazine compound, this compound may be applied to the photographic assembly as a preformed reduced compound.
The methods of forming a reduced derivative of 1,4-diazine compound are described in British Patent Specification No.
1183176.
Alterr.atively, and this is preferred, the reduced diazine compound is produced during the processing step from a diazine compound or from a N-oxide derived therefrom by use Or a reducing agent in iayer form in an acid medium, the said reducing agent being a metal which in the electro-chemical series of the elements is above silver and up to and including aluminium. This method of processing is described in B.P. Spec;fication No. 1330755.
~2~
For the present invention the reducing agents can be metals, which are in the electrochemical series above silver and up to and including lanthanum, preferably up to and includïng aluminium, such metals are e.g.: copper iron, lead, tin, nickel, cobalt, indium gallium, cadmium, manganese, aluminium and lanthanum. Further alloys con-taining these metals or said metals in amalgamated form can be used.
For example there may be used a vacuum deposited coated metal strip for example a tin or copper film base strip and there is coated on to this coated strip or on the exposed photographic material a solution or paste which comprises a 1,4-diazine compound in an acid solution. The diazine compound is reduced by the metal and diffuses into the photographic material where the reduced diazine compound in the presence of the acid solution acts as a developing agent for the exposed silver halide.
Alternatively there may be present in the photographic material a layer which contains a fine or colloidal dis-persion of a metal which in the electrochemical series is above silver and up to and including aluminium. In fact a colloidal dispersion of aluminium is particularly useful.
In a further alternative method the reduced diazine compounds may be formed in the assembly during the development step by electrolysis.
Similarly if the bleach-developer compound comprises simple or complexed metallic ions in a reduced state these ions may be prepared and applied to the photographic assembly , Z~
in a number of dif~erent ways.
For example al~a preformed acid solution o~ the metallic ions may be used~ bl)the acid solution of the metallic ions may be formed externally to the photographic assembly but as a step in the processing sequence, cl)the acid solution of the simple or complexed reduced metallic ions may be formed in situ in the photographic assembly during the processin~ sequence.
Thus in the method ~) above the reduced metal ion may be preformed by known methods, such as electrolytic reduction of a suitable oxidised form or ~ormation of the required metal ion complex by admixture of suitable starting materials ;in the required oxidation state.
When method bl~is used a ~rip (foi~o a second metal or a strip having a fine colloid dispersion of a second metal coated thereon is used: the second metal having a reduction potential sufflciently negat;ve to achieve reduction of the oxidised form of the metallic ion to the reduced rorm of ,~. . .
the metallic ion. The metal strips are e.g. composed of aluminium, iron, ~inc or tin; ~urther of indium or alloys which include such metals. When employed in a ~ine colloid dispersion the metals are for example zinc, tin, iron~
nickel, aluminium or indium may be used; fu~tller gallium lanthanum, or alloys containing these metals.
There is coated on to this coated strip which is then applied to the exposed photographic assembly a solution or paste which comprises an oxidised form Or the metalli~ ion in acid solution. The oxidised form Or the metallic ion is reduced by the second metal and diffuses into the photo-graphic assembly where the reduced form of the metallic ion in the presence of the acid solution acts as a developing agent for the latent silver halide. In case cl)there may be present in the photographic assembly a layer ~hich con-tains a fine or colloid dispersion of a second metal which can reduce oxidised forms of ~he metallic ions to produce the active form of the ions. Such metals are alumin-ium, copper~zinc, tin,iron, nickel, gallium or indium, further lanthanum or alloys which include such metals. Also in ~e~hod cl) the reduced metallic ions may be formed electrolyti-cally in the assembly during the silver halide developing step.
.
Preferred metals amongst these are those which do not react rapidly with atmospheric oxygen and water at room temperature.
If desired, complex-forming agents for the metals can also be employed during processing.
For example, ~he fluoride ion forms complexes with aluminium-III ions and the copper-I ion is bonded as a complex by, for example, nitriles, olefines, chloride ions, bromide ions and thioethers. ~A large number of ligands and also the stability constants of the complexes formed therefrom with various metal ions are listed in the book "Stability Constants of Metal-Ion Complexes, Special Publi-cation No. 17, London: The Chemical Society~ Burlington House, W.l., 1964". During processing, a complex-bonded metal ion forms from the complex-formirlg agent (for example fluoride ions from ~H4~ or CaF2 for Al), incorporated in the processing solution or in the material, and the metal, which is present ir, the form of a layer in the photographic material or is brought into contact with the photographic material during processing, with interposition of the pro-cessing bath, and by this means an increase ln the reactivity of the metal is achieved.
.
The use of sparingly soluble compounds as donors of complex-forming agents, for example CaF2 as a fluoride ion donor, has the advantage that an adequate amount of ligand for forming the complex is available without, at the same time, a momentarily undesirable high excess of ligand being present in the solution.
The metals can be distributed in the form of small particles in a layer containing a silver salt or in an adjacent auxiliary layer which may be present. Auxiliary layers can be bonded to the silver salt emulsion layer in an inseparable or readily separable manner. The particles can be dispersed direct in a layer colloid or can addition-ally be surrounded by a coating`of a polymeric substance.
Furthermore, the metal particlès can be contained in cap-sules which can be broken open by a change in pressure, temperature or pH. In addition the metals can be supplied for use from small particles of a polymeric substance pro-vided with a metallic coating.
-h~
- z3 -Various embodiments of photographic assemblies of use in the present invention will now be described with refer-ences-to the accompanying figures 1 to 23.
Figures 1 to 13 show assemblies which comprise either a stripping position or stripping layer.
,, .. . .. ~ . . .. ^ . --- . -- - - . --. .. . .. .. . . .. .. . , . ....... .... , . _ .. ..
Figures 14 to 19 show integral assemblies.
Figures 20 to 22 show assemblies which comprise a photosensitive portion and an image portion which are only brought together during processing.
Figure 23 shows an assembly in two sections suitable for in-camera processing.
In figures 1 to 13 the term stripping position has been used, however this may be either an ir.terface between layers at which adhesion failure may occur or it may indi-cate an actual stripping layer.
In figure 1 there is shown a photographic material according to the present invention which can be used for X-ray film material.
As shown in figure 1 the material comprises a trans-parent support l having coated thereon a bleachable dye-in-gelatin layer 2. Abovè this is the stripping position 3. Above the stripping position 3 is a carbon black layer 4 and above this a conventional silver halide emulsion layer 5, then a carbon black layer 6 and above is a supercoat layer 7. Thus the silver halide emulsion layer 5 is sandwiched between two carbon black layers ll - ~4 -and 6 and therefore the photographic material can be handled in daylight. The material may be exposed to X-rays and a~ter exposure it can bè processed using an aqueous acid solution of the bleach-developer compound as just described to yield a negative silver image. The silver halide layer and the two carbon black layers and ~the supercoat layer are then stripped off ~he dye layer for recovery~of the silver. The negative dye image on the support can ~hen be viewed by transmission.
For convenience the expression "X-ray" as used in the speci~ication is intended to cover all very short wave photographically useful radioactive rays such as those émanating from an X-ray tube, radium or radioact;ve iso-topes.
In figure 2 there is shown photographic material according to the present invention which can be used as X-ray material for reflection viewing. In this embodiment there is coated on a transparent film support 1 in order a bleachable dye-in-gelatin layer 2, a white opaque layer 3, stripping position 4, a carbon black layer r, a conventional silver halide emulsion layer 6,~ a carbon black layer 7 and a supercoat layer 8.
In this case as in the case of the material o~ figure l the photographic material is processed to yield a negative image. But in this material an extra white opaque layer is present. This may consist f'or example Or baryta or - ~
Z~
titanium oxide dispersed in gelatin. In this rnaterial the whike opaque layer acts as a reflective base ~or the negative dye image which is viewed by reflection through the film support.
, . .
Figure 3 shows an alternative embodiment of the material of figure 2. In this figure the layers have the same numbers as in figure 2 but the stripping position has now been altered and is between the lower carbon b~ack layer 5 and the silver halide emulsion layer 6. When the silver halide emulsion layer is stripped off after process-ing the carbon black layer is then attached to the white opaque layer.
The main advantages of the photographic material as described with references to rigures 1 to 3 is that all silver in the silver halide emulsion layer may be recovered and the film material is insensitive to daylight and thus may be handled in the unexposed state in normal daylight conditions. However the photographic material of the present invention can also be used in a norr.;al camera or process camera if the top carbon black layer is omitted.
Such material in which there is no carbon black layer at all is shown in the accompanying figure 4 in which there is coated on an opaque ~upport 1 in order a bleachable dye-in-gelatin layer 2, stripping posit;on 3, a silver halide emulsion layer 4 and a supercoat layer 5. Prerer-ably this material comprises in layer 4 a direct positive emulsion and thus l~hen processed yields a d rect positive dye image which is viewed by reflection. In this case the material cannot be handled at any stage in daylight conditions before the silver halide layer has been stripped of~.
Yet another embodiment of the material of the present invention .s shown in the accompanying figure 5. In this material there is coated on a transparent support 1 i~
order a bl~achable dye-in-gelatin layer 2, stripping posi-tion 3, carbon black layer 4, silver halide emulsion layer .~ .
5 and supercoat layer 6. In this case the material pro-duces a final dye image which may be viewed by transmission.
In the case of this material exposure must be in a camera or other light-tight exposure chamber. However if the material is processed by a method wherein an activator metal foil which is light opaque is placed in contact ~ith the photographic material on the supercoat side then the processing may be carried out under daylight conditions.
Another embodiment of the invention is shown in figure 6 in which there is coated on ~a transparent support 1``
in order a bleachable dye-in-gelatin layer 2, white opaque layer ~, carbon black layer 4, stripping position 5, silver halide layer 6 and supercoat layer 7. In this case also, exposure must be in a camera or light-tight exposure chamber.
The silver halide emulsion layer 6 may be a direct positive emulsion and in which case after processing there is pro-duced a direct positive image which is viewed by reflection.
.. . . .. . ... .. .....
Alternatively if a conventional silver halide emulsion is used there is produced a nega~ive image which is viewed by reflection, although of course it would be more usual in this case to employ material which would produce a direct positive image as the image is viewed by reflection unless exposure were to X-rays when it is usual to view negative images.
The assemblies shown in Figures 1 to 6 may be processed by the application of an acid solution which comprises a bleach-developer compound. This bleach-developer compound may be a preformed reduced azine for example the dihydro derivative of methyl acetyl quinoxaline which remains as the active compound for some time especially if kept under a nitrogen atmosphere. However bleach-developer compounds which comprise an aqueous acid solution of metallic ions in their lower valency state are especially suitable, e.g.
titanous ions stabilised with ethylene diamine tetraacetic acid. Such solutions remain active for some time. Altern-atively as men~ioned with reference to figure 5 the inactive bleach-developer solution can be used together with an activator metal foil e.g. aluminium or zinc foil, ~he metal reducing the inactive bleach-developer to the active form as it contacts the photographic assembly.
Such methods Or processing are shown in ~igures 7 and
- 2~ -8. In figure 7 the photographic assernbly comprises a white reflecting support 1 on which is roated a bleachable dye-in-gelat,in layer 2. A stripping position
3 is present between layer 2 and layer 4 whîch is a black opaque layer and coated on layer 4 is a silver halide emulsion layer 5 on which is coated a thin supercoat layer 6.
The inactive bleach-developer solution is applied to the supercoat layer 6 and the assembly is then contacted with a zinc paste layer 7 which is coated on to a black opaque paper support 8, The material of figure 7 can be processed in the light after the black paper has been brought into contact there-with.
A dye image is obtained in the image layer 2 and layers 4-8 are stripped off.
` In figure 8 the material of figure 5 is shown with an aluminium foil 7 above it. After exposure the inactive bleach-developer acid solution is placed on the supercoat layer 6 and the metal foil pressed in contact therewith.
Figures 9 1~ show similar assembli,es to those of figures 1-6 in that each comprises a stripping layer but in the case of the assemblies 9-1~ each also comprises,a metal activating layer. .
The assembly of figure 9 is similar to the assembly of'figure 4 but there is prese,nt in the supercoat layer 5 a dispersion of zinc powder.
The assembly of figure 10 is somewhat similar to that of figure 4 except that coated on the metal layer 5 is another silver hal.de emulsion layer 6 and coated on that a thin supercoat layer 7. The presence of the second silver halide emulsion layer is to enhance the dye image formed in layer 2.
z~
The assembly of figure 11 is similar to the assembly shown in figure 1 except that in the carbon black layer 6 of figure 1 there is present a fine dispersion of alumi~ium metal particles.
In the assembly shown in figure 12 there is a trans-parent support 1 on which is coated a bleachable dye-in-gelatin layer 2, a white reflecting layer 3~ a silver halide emulsion layer 5, a copper particle layer 6 and a silver ;halide emulsion layer 7. After exposure an inactive bleach-developer solution is applied to the emulsion layer 7 and this diffuses down to the metal layer 6 where it becomes activated. The act;ve bleach-developer compound develops the latent image ir. both of the silver halide emulsion layers and in the non-latent image areas diffuses to the -- bleachable dye layer 2 where it bleaches the dye to form a dye image. The stripping layer 4 is then activated and the dye image can be viewed through the base against the white reflecting layer 3. The effect of the two silver halide emulsion layers is to strengthen the dye image formed in layer 2.
The assembly shown in figure 13 is similar to the assembly shown in figure 4 except that the supercoat layer 5 of figure 4 comprises a fine dispersion of zinc metal flakes.
Processing of the assemblies shown in figures 9-13 is carried out by applying to the topmost layer an acid solution of an inactive bleach-developer compound, When the inactive bleach~developer compound reaches the metal layer it becomes active and is able to develop the latent silver image in the silver halide emulsion layer or layers and afteP diffusion into the bleachable dye layer there to bleach the dye to form an image.
Photographic assemblies of use in the present invention which are integral, i.e. which remain in one piece after processing are shown in figures 14~
In figure 14 there is coated on a support 1 in o~der a bleachable dye-in-gelatin layer 2~ a white reflecting layer 3, a carbon black opacifying layer 4, a silver halide emulsion layer 5 and a supercoat layer 6. Exposure must be in a camera or light-tight exposure chamber. The emulsion layer 5 may be chosen to produce a direct positive image or a negative image.
In figure 15 there is coated on a support 1 in order a bleachable dye-in-gelatin layer 2, a white reflecting layer 3, a carbon black opacifying layer 4, a silver halide emulsion layer 5, a carbon black opaci~ying layer 6 and a supercoat layer 7. Exposure of this material must be to X-rays. The silver halide emulsion of this layer would normally be a conventional emulsion so yielding a negative image to be viewed by refiection as X-ray fi'ms are by custom processed to yield negative images.
In an alternative embodiment shown in figure 16 layer 6 instead of being a carbon black opacifying layer is a zinc powder + carbon black opacifying layer. Such material can be processed after exposure to yield a dye image therein by application of an acid solution of an unreduced bleach-development compound of the type wherein the reduced form acts as a silver halide developing agent.
The assembly of figure 17 is similar to that of figure 16 except that the carbon black f zinc layer is located between the silver halide emulsion layer and the white reflecting layer and there is no top carbon black layer.
The assemblies of figures 15 and 16 can be exposed only to X-rays but can be daylight processed whilst ~he assembly of figure 17 is light-sensitive and the usual precautions must be taken during exposure and also during processing unless a light-opaque mask is placed over the assembly during processingO
.
In the assembly shown in figure 18 a transparent support 1 has coated thereon a bleachable dye layer 2, a white reflecting layer 3, a silver halide emulsion layer
The inactive bleach-developer solution is applied to the supercoat layer 6 and the assembly is then contacted with a zinc paste layer 7 which is coated on to a black opaque paper support 8, The material of figure 7 can be processed in the light after the black paper has been brought into contact there-with.
A dye image is obtained in the image layer 2 and layers 4-8 are stripped off.
` In figure 8 the material of figure 5 is shown with an aluminium foil 7 above it. After exposure the inactive bleach-developer acid solution is placed on the supercoat layer 6 and the metal foil pressed in contact therewith.
Figures 9 1~ show similar assembli,es to those of figures 1-6 in that each comprises a stripping layer but in the case of the assemblies 9-1~ each also comprises,a metal activating layer. .
The assembly of figure 9 is similar to the assembly of'figure 4 but there is prese,nt in the supercoat layer 5 a dispersion of zinc powder.
The assembly of figure 10 is somewhat similar to that of figure 4 except that coated on the metal layer 5 is another silver hal.de emulsion layer 6 and coated on that a thin supercoat layer 7. The presence of the second silver halide emulsion layer is to enhance the dye image formed in layer 2.
z~
The assembly of figure 11 is similar to the assembly shown in figure 1 except that in the carbon black layer 6 of figure 1 there is present a fine dispersion of alumi~ium metal particles.
In the assembly shown in figure 12 there is a trans-parent support 1 on which is coated a bleachable dye-in-gelatin layer 2, a white reflecting layer 3~ a silver halide emulsion layer 5, a copper particle layer 6 and a silver ;halide emulsion layer 7. After exposure an inactive bleach-developer solution is applied to the emulsion layer 7 and this diffuses down to the metal layer 6 where it becomes activated. The act;ve bleach-developer compound develops the latent image ir. both of the silver halide emulsion layers and in the non-latent image areas diffuses to the -- bleachable dye layer 2 where it bleaches the dye to form a dye image. The stripping layer 4 is then activated and the dye image can be viewed through the base against the white reflecting layer 3. The effect of the two silver halide emulsion layers is to strengthen the dye image formed in layer 2.
The assembly shown in figure 13 is similar to the assembly shown in figure 4 except that the supercoat layer 5 of figure 4 comprises a fine dispersion of zinc metal flakes.
Processing of the assemblies shown in figures 9-13 is carried out by applying to the topmost layer an acid solution of an inactive bleach-developer compound, When the inactive bleach~developer compound reaches the metal layer it becomes active and is able to develop the latent silver image in the silver halide emulsion layer or layers and afteP diffusion into the bleachable dye layer there to bleach the dye to form an image.
Photographic assemblies of use in the present invention which are integral, i.e. which remain in one piece after processing are shown in figures 14~
In figure 14 there is coated on a support 1 in o~der a bleachable dye-in-gelatin layer 2~ a white reflecting layer 3, a carbon black opacifying layer 4, a silver halide emulsion layer 5 and a supercoat layer 6. Exposure must be in a camera or light-tight exposure chamber. The emulsion layer 5 may be chosen to produce a direct positive image or a negative image.
In figure 15 there is coated on a support 1 in order a bleachable dye-in-gelatin layer 2, a white reflecting layer 3, a carbon black opacifying layer 4, a silver halide emulsion layer 5, a carbon black opaci~ying layer 6 and a supercoat layer 7. Exposure of this material must be to X-rays. The silver halide emulsion of this layer would normally be a conventional emulsion so yielding a negative image to be viewed by refiection as X-ray fi'ms are by custom processed to yield negative images.
In an alternative embodiment shown in figure 16 layer 6 instead of being a carbon black opacifying layer is a zinc powder + carbon black opacifying layer. Such material can be processed after exposure to yield a dye image therein by application of an acid solution of an unreduced bleach-development compound of the type wherein the reduced form acts as a silver halide developing agent.
The assembly of figure 17 is similar to that of figure 16 except that the carbon black f zinc layer is located between the silver halide emulsion layer and the white reflecting layer and there is no top carbon black layer.
The assemblies of figures 15 and 16 can be exposed only to X-rays but can be daylight processed whilst ~he assembly of figure 17 is light-sensitive and the usual precautions must be taken during exposure and also during processing unless a light-opaque mask is placed over the assembly during processingO
.
In the assembly shown in figure 18 a transparent support 1 has coated thereon a bleachable dye layer 2, a white reflecting layer 3, a silver halide emulsion layer
4 and a sup~rco~ layer 5 which comprises fine zinc metal plates.
Application of an acid solution of an inactive bleach-developer causes the bleach-developer to diff'use into the metal layer where it becomes activated and ~hen to the silver halide emulsion layer where the bleach~developer compound develops the latenk silver image. In the non-latent images areas it diffuses to the bleachable dye layer whereit contra-silver-imagewise bleaches the dye to form a dye image.
The assembly of figure 19 is similar to that of figure 18 except that coated on layer 5 is another silver halide emulsion layer 6. The effect of the second silver halide emulsion layer is to reinforce the final dye image in layer 2.
In none of the assemblies shown in figu-~es 14-19 is there a stripping position or layer. This means that all the silver present initially is still present in the final image material. However it is possible to make use of a very low coating weight of silver which when the material is exposed and processed yields a very low density ;mage, too low in fact to be of use as a final image. However the final image in the assemblies of figures 14-19 is a dye image of very acceptable density as a final image.
Thus the amount of silver used can be small as the silver is used merely as the radiation sensitive agent and not as the image-producing substance as well although it is s~ill present in the asserllbly but is invisible as it is on the other side of the white reflecting layer to the dye image.
In figure 20 there is shown a photographic assembly of use in the present invention which comprises two se-parate components. The image component consists of a transparent support 1 on which is coated a bleachable dye-in-gelatin layer 2. The photosensitive component comprises a supercoat layer 6 which is transparent but which is sufficiently thick and rigid to act as a support. On layer 6 is coated a metal powder (e.g. aluminium, zinc or copper) and gelatin binder layer 5. On layer 5 is coated a camera speed silver halide emulsion layer 4.
Between layer 4 and layer 2 there is shown a pod 3 which contains an acid solution of a bleach-developer compound in its higher valency state but which in its lower valency state is able to act both as a silver halide developing agent and as a dye bleaching agent.
The assembly of figure 20 is of use in a self- , processing camera of the type known per se. In operation the assembly preferably with the pod 3 already in position between the two components of the assembly is imagewise exposed through the supercoat layer 6. After exposure the assembly is led through a pair of driven rollers which rupture the pod 3 and cause the processing fluid contained therein to spread evenly between the two components and it also brings the two components into very close contact.
The unreduced bleach-development compound in the acid solution then diffuses into both components but is not able to either develop the latent image in the silver halide nor bleach the dye until some of the compound has reached layer 5. There it is reduced to the active form.
The reduced compound then diffuses through the assembly.
In layer 4 it develops the latent image areas and is de-activated. In the non-latent image areas it continues to diffuse down through the thin layer of solution between layers 4 and 2 and into layer 2 where it acts to bleach the imagewise bleachable dye to form a dye image.
- 3~ -In this case as a camera speed emulsion is used the emulsion is preferably a negative emulsion. Thus a negative dye image will be formed.
The assembly of figure 21 is similar to that of figure 20 except that in the silver halide emulsion layer 4 there is also present fine particles of zinc dust and no metal layer 5.
In figure 22 there is shown another photographic assembly of use in the present invention which comprises two separate components. The lower component comprises a transparen~ support, a neutralising layer 2, a bleach-able dye(s) ~ gelatin layer 3. The upper component com-prises coated on a paper base 4 a zinc powder + binder layer
Application of an acid solution of an inactive bleach-developer causes the bleach-developer to diff'use into the metal layer where it becomes activated and ~hen to the silver halide emulsion layer where the bleach~developer compound develops the latenk silver image. In the non-latent images areas it diffuses to the bleachable dye layer whereit contra-silver-imagewise bleaches the dye to form a dye image.
The assembly of figure 19 is similar to that of figure 18 except that coated on layer 5 is another silver halide emulsion layer 6. The effect of the second silver halide emulsion layer is to reinforce the final dye image in layer 2.
In none of the assemblies shown in figu-~es 14-19 is there a stripping position or layer. This means that all the silver present initially is still present in the final image material. However it is possible to make use of a very low coating weight of silver which when the material is exposed and processed yields a very low density ;mage, too low in fact to be of use as a final image. However the final image in the assemblies of figures 14-19 is a dye image of very acceptable density as a final image.
Thus the amount of silver used can be small as the silver is used merely as the radiation sensitive agent and not as the image-producing substance as well although it is s~ill present in the asserllbly but is invisible as it is on the other side of the white reflecting layer to the dye image.
In figure 20 there is shown a photographic assembly of use in the present invention which comprises two se-parate components. The image component consists of a transparent support 1 on which is coated a bleachable dye-in-gelatin layer 2. The photosensitive component comprises a supercoat layer 6 which is transparent but which is sufficiently thick and rigid to act as a support. On layer 6 is coated a metal powder (e.g. aluminium, zinc or copper) and gelatin binder layer 5. On layer 5 is coated a camera speed silver halide emulsion layer 4.
Between layer 4 and layer 2 there is shown a pod 3 which contains an acid solution of a bleach-developer compound in its higher valency state but which in its lower valency state is able to act both as a silver halide developing agent and as a dye bleaching agent.
The assembly of figure 20 is of use in a self- , processing camera of the type known per se. In operation the assembly preferably with the pod 3 already in position between the two components of the assembly is imagewise exposed through the supercoat layer 6. After exposure the assembly is led through a pair of driven rollers which rupture the pod 3 and cause the processing fluid contained therein to spread evenly between the two components and it also brings the two components into very close contact.
The unreduced bleach-development compound in the acid solution then diffuses into both components but is not able to either develop the latent image in the silver halide nor bleach the dye until some of the compound has reached layer 5. There it is reduced to the active form.
The reduced compound then diffuses through the assembly.
In layer 4 it develops the latent image areas and is de-activated. In the non-latent image areas it continues to diffuse down through the thin layer of solution between layers 4 and 2 and into layer 2 where it acts to bleach the imagewise bleachable dye to form a dye image.
- 3~ -In this case as a camera speed emulsion is used the emulsion is preferably a negative emulsion. Thus a negative dye image will be formed.
The assembly of figure 21 is similar to that of figure 20 except that in the silver halide emulsion layer 4 there is also present fine particles of zinc dust and no metal layer 5.
In figure 22 there is shown another photographic assembly of use in the present invention which comprises two separate components. The lower component comprises a transparen~ support, a neutralising layer 2, a bleach-able dye(s) ~ gelatin layer 3. The upper component com-prises coated on a paper base 4 a zinc powder + binder layer
5, a silver halide emulsion layer 6 and a supercoat layer 7. The lower component may be part of a long web of material.
In operation after the upper component has been image-wise exposed in a camera through the supercoat layer 7 the upper component is placed juxtaposed the lower compor.~nt, layer 7 facing layer 3. Then an inactive form Or bleach-developer compound is spread either as a dispersion or as a solution on either layer 7 or layer 3 and the two compon~
ents are held together in close contact.
The inactive bleach-developer compound then diffuses into layer 5 where it is converted to the active form.
It then diffuses into layer 6 where in the latent image areas it develops the latent silver image whilst in the non-latent in~age areas it diffuses in counter-imagewise fashion through the protective layer 7 to the dye layer 3 where it bleaches the dye thus yielding a dye image. The upper con!ponent can then be removed and the silver recovered therefrom. The image can be viewed through the transparent base. In practice if the lo~er component is part of a web a series ~f dye irnages will be present along the length of .
the web if the process has been repeated using a series of exposed upper components.
ln figure 23 there is sho~m a photogra~hic assembly of use in the present invention which comprises two separate components. The first component consists only of a separ-ate supercoat 5. The other component comprises a trans-parent support 1 having coated thereon in order a bleachable image dye layer 2, a white reflecting layer 3, and a silver halide layer 4. Between the supercoat layer 5 and the silver halide layer 4 is shown a pod 6 which con-tains a preformed bleach-developer compound.
The assembly o~ figure 23 is of use in a self-pro-cessing camera of the type known per se. In op-~a~-on the assembly with the supercoat layer 5 in close contact with the silver halide emulsion layer 4 is imagewise exposed in a camera. Preferably the pod 6 s present in the assembly with i~s outlet between two edges of the super-coat and silver halide layers but is so positioned that close optical contact between these two layers is not impaired.
After exposure the assembly is led through a pair of ~riven rollers which rupture the pod 6 and cause the pro-cessing fluid contained therein to spread evenly between the supercoat layer 5 and the silver halide layer 4. The preformed bleach-developer compound then diffuses into the silver halide layer and develops the latent image therein in the latent image areas. In the non-latent image areas it diffuses in a counter-imagewise manner through the white reflecting layer 3 and into the dye(s) + gelatin layer 2 where it bleaches the bleachable layer to form a dye image. The image can then be viewed by reflection through the support 1.
An example o~ a suitable white re~lecting layer for use in khe material of figures 2, 3, 6, 8, 12, 14-19 and 23 is as follows:-Titanium dioxide (mean particle size 1.5~) 15 g -Gelatin (4~0 aqueous solukion) 50 ml Sodium dodecyl sulphate (28% aqueous solution) 0.3 ml Aryl alkyl polyethylene oxide condensate 3.0 ml (6% solution in 50/50 ethanol/water) .
dispersed using a homogeniser or ulkrasonic mixer coated to give a layer containing 27 g.m. 2 TiO2.
An example of a suitable carbon black layer for use in the material of figures 1-3, 5-8, 11 and 14-17 is as follows:-Gelatin 3 g Water 40 ml Carbon black dispersion 5 ml Wetting agent 2.5 ml (5% aqueous solukion) mixed gently for two minutes coated to give a layer containing 2.7 g.m. ~ C.
.
.. .. .... .. .
There may be present in the photographic material ofthe present invention yek other layers for example a neuk-ralising layer, a timing layer,~ a mordank layer which may be used to trap amines released during the bleaching of azo dyes when such dyes are used as the image dye, or a layer to control the swelling of the gelatin layers. Prefer-ably any of the above layers~ if present, are located between the supercoat layer and the silver halide emulsion layer or bekween the dye layer and the support 90 as not to prolong nor inter~ere with the dif~usion path o~ the bleach development compound to the bleachable dye layer~
The preferred binder for all layers is ~elatin.
However so-called gelatin extenders may be present for example those derived from synthetic colloid latexes, especially acrylic latexes. Other natural or synthe~ic binders may be used either alone or in admixture with the gelatin~ for example albumin, casein, polyvinyl alcohol and polyvinyl pyrrolidone.
- The halide content and ratio of the silver halide present in the silver halide emulsion layer depends on how the material is to be used but all the usual pure bromide, chlorobromide, iodobromide and chlorobromoiodide æilver halides are of use in the photographic material in use in the process of the present invention. There may also be present in the silv~er~ halide emulsion layer any-o~ the usual addenda present in silver halide emulsion layers such as sulphur and gold sensitisers, emulsion stabi-lizers, wetting agents and antifoggants.
The support used ~ay be of any of the usual supports used for photographic materials, for example if the support is transparent it may be composed of cellulose triacetate 9 cellulose acetatebutyrate, oriented and subbed polystyrene polycarbonate or polyester, such as polyethylene tereph-thalate. If the support is opaque it may be of any of the above listed ~ilm base materials which has been pigmented for example with barium sulph`ate or titanium dioxide to render its coated surface reflecting, or it may be a paper support having a baryta coating thereon or poly-ethylene coated paper base. Alternatively it may be voided polyester support.
As hereinbefore stated processin~ is preferably carried out in an aqueous medium and this is pre~erably rendered acid with a suitable acid or a buffer mixture, advantage-ously to a pH value bctween O and 4. The processing and developing speed and the gradation can be varied within~
~ide limits, as a function of the pH value. Preferred suitable acids are: aliphatic, aromatic or heterocyclic mono-,di- and tri-carboxylic acids, which can also contain substituents such as chlorine, bromine and iodine atoms or hydroxyl, nitro~ amino or acylamino groups, and also aliphatic or aromatic sulphonic acids or phosphoric acid and mineral acids such as HF, HCl, HBr, HC104, HN03, H2S04, H3P04 and H2C03; also HS03 , S02, sulphamic.acid.
Suitable buffers are: [Al(H20)6]3~, HBF4, Na2S207 or Na2S25 -Preferably an antifoggant is present in the aqueous acid processing medium ~or example iodide or bromide ions or l-phenyl-5-mercs}to-tetrazole.
.
The following Examples will serve to illustrate the invention.
Photographic material as shown in figure 4 was pre-pared by coating sequentially onto O.1 mm thick white pigmented cellulose triacetate support the following layers.
1. A gelatin layer containing 0.2 g.m. 2 of the dyestuff -CO-NH OH ~ Oyl~
~ ~ N = N < ~ -N = N- ~\) H03S~ S03H OCH3 SO~H
in gelatin 4.0 g m.-2.
2. A stripping layer consisting of phthala-ted gelatin with a gelatin coating weight of 1.0 g.m.
3. A photosensitive silver halide gelatin emulsion layer containing 1.2 g.m. 2 silver in the form of silver chloro-bromide (70 mol% of AgCl and 30 mol~ of AgBr).
4. A supercoat layer containing gelatin 1.0 g.m.
After exposure to light behind a grey wedge, the ma-terial was processed in the dark by contacting the emul-sion side with an aluminiumised support onto which had been applied a processing composition of the following formulation:
Pyrazine 0.~ g Sulphuric acid (5N) 8.0 ml Calcium fluoride 0.1 g Hydroxyethyl cellulose 1.0 g (Natrosol type 250 HH) (trademark) Water to 100 ml After five minutes the aluminiumised support was removed. During this period the processing solution had softened the phthalated gelatin layer and when the alumin-iumised support was removed the silver halide layer and supercoat layer were removed with it to reveal a cyan image of the wedge present on the support. The density of this image was acceptably dark as a final image.
-A material as depicted in figure 15 was prepared by coating sequentially onto a 0.1 mm thick uncoloured transparent cellulose triacetate support the following layers:
1. A gelatin layer containing the same dye as used in Example 1.
2. A white reflecting layer.
3. A black opacifying layer.
4. An emulsion layer as used in Example 1.
5. A zinc powder plus carbon black opacifying layer.
In operation after the upper component has been image-wise exposed in a camera through the supercoat layer 7 the upper component is placed juxtaposed the lower compor.~nt, layer 7 facing layer 3. Then an inactive form Or bleach-developer compound is spread either as a dispersion or as a solution on either layer 7 or layer 3 and the two compon~
ents are held together in close contact.
The inactive bleach-developer compound then diffuses into layer 5 where it is converted to the active form.
It then diffuses into layer 6 where in the latent image areas it develops the latent silver image whilst in the non-latent in~age areas it diffuses in counter-imagewise fashion through the protective layer 7 to the dye layer 3 where it bleaches the dye thus yielding a dye image. The upper con!ponent can then be removed and the silver recovered therefrom. The image can be viewed through the transparent base. In practice if the lo~er component is part of a web a series ~f dye irnages will be present along the length of .
the web if the process has been repeated using a series of exposed upper components.
ln figure 23 there is sho~m a photogra~hic assembly of use in the present invention which comprises two separate components. The first component consists only of a separ-ate supercoat 5. The other component comprises a trans-parent support 1 having coated thereon in order a bleachable image dye layer 2, a white reflecting layer 3, and a silver halide layer 4. Between the supercoat layer 5 and the silver halide layer 4 is shown a pod 6 which con-tains a preformed bleach-developer compound.
The assembly o~ figure 23 is of use in a self-pro-cessing camera of the type known per se. In op-~a~-on the assembly with the supercoat layer 5 in close contact with the silver halide emulsion layer 4 is imagewise exposed in a camera. Preferably the pod 6 s present in the assembly with i~s outlet between two edges of the super-coat and silver halide layers but is so positioned that close optical contact between these two layers is not impaired.
After exposure the assembly is led through a pair of ~riven rollers which rupture the pod 6 and cause the pro-cessing fluid contained therein to spread evenly between the supercoat layer 5 and the silver halide layer 4. The preformed bleach-developer compound then diffuses into the silver halide layer and develops the latent image therein in the latent image areas. In the non-latent image areas it diffuses in a counter-imagewise manner through the white reflecting layer 3 and into the dye(s) + gelatin layer 2 where it bleaches the bleachable layer to form a dye image. The image can then be viewed by reflection through the support 1.
An example o~ a suitable white re~lecting layer for use in khe material of figures 2, 3, 6, 8, 12, 14-19 and 23 is as follows:-Titanium dioxide (mean particle size 1.5~) 15 g -Gelatin (4~0 aqueous solukion) 50 ml Sodium dodecyl sulphate (28% aqueous solution) 0.3 ml Aryl alkyl polyethylene oxide condensate 3.0 ml (6% solution in 50/50 ethanol/water) .
dispersed using a homogeniser or ulkrasonic mixer coated to give a layer containing 27 g.m. 2 TiO2.
An example of a suitable carbon black layer for use in the material of figures 1-3, 5-8, 11 and 14-17 is as follows:-Gelatin 3 g Water 40 ml Carbon black dispersion 5 ml Wetting agent 2.5 ml (5% aqueous solukion) mixed gently for two minutes coated to give a layer containing 2.7 g.m. ~ C.
.
.. .. .... .. .
There may be present in the photographic material ofthe present invention yek other layers for example a neuk-ralising layer, a timing layer,~ a mordank layer which may be used to trap amines released during the bleaching of azo dyes when such dyes are used as the image dye, or a layer to control the swelling of the gelatin layers. Prefer-ably any of the above layers~ if present, are located between the supercoat layer and the silver halide emulsion layer or bekween the dye layer and the support 90 as not to prolong nor inter~ere with the dif~usion path o~ the bleach development compound to the bleachable dye layer~
The preferred binder for all layers is ~elatin.
However so-called gelatin extenders may be present for example those derived from synthetic colloid latexes, especially acrylic latexes. Other natural or synthe~ic binders may be used either alone or in admixture with the gelatin~ for example albumin, casein, polyvinyl alcohol and polyvinyl pyrrolidone.
- The halide content and ratio of the silver halide present in the silver halide emulsion layer depends on how the material is to be used but all the usual pure bromide, chlorobromide, iodobromide and chlorobromoiodide æilver halides are of use in the photographic material in use in the process of the present invention. There may also be present in the silv~er~ halide emulsion layer any-o~ the usual addenda present in silver halide emulsion layers such as sulphur and gold sensitisers, emulsion stabi-lizers, wetting agents and antifoggants.
The support used ~ay be of any of the usual supports used for photographic materials, for example if the support is transparent it may be composed of cellulose triacetate 9 cellulose acetatebutyrate, oriented and subbed polystyrene polycarbonate or polyester, such as polyethylene tereph-thalate. If the support is opaque it may be of any of the above listed ~ilm base materials which has been pigmented for example with barium sulph`ate or titanium dioxide to render its coated surface reflecting, or it may be a paper support having a baryta coating thereon or poly-ethylene coated paper base. Alternatively it may be voided polyester support.
As hereinbefore stated processin~ is preferably carried out in an aqueous medium and this is pre~erably rendered acid with a suitable acid or a buffer mixture, advantage-ously to a pH value bctween O and 4. The processing and developing speed and the gradation can be varied within~
~ide limits, as a function of the pH value. Preferred suitable acids are: aliphatic, aromatic or heterocyclic mono-,di- and tri-carboxylic acids, which can also contain substituents such as chlorine, bromine and iodine atoms or hydroxyl, nitro~ amino or acylamino groups, and also aliphatic or aromatic sulphonic acids or phosphoric acid and mineral acids such as HF, HCl, HBr, HC104, HN03, H2S04, H3P04 and H2C03; also HS03 , S02, sulphamic.acid.
Suitable buffers are: [Al(H20)6]3~, HBF4, Na2S207 or Na2S25 -Preferably an antifoggant is present in the aqueous acid processing medium ~or example iodide or bromide ions or l-phenyl-5-mercs}to-tetrazole.
.
The following Examples will serve to illustrate the invention.
Photographic material as shown in figure 4 was pre-pared by coating sequentially onto O.1 mm thick white pigmented cellulose triacetate support the following layers.
1. A gelatin layer containing 0.2 g.m. 2 of the dyestuff -CO-NH OH ~ Oyl~
~ ~ N = N < ~ -N = N- ~\) H03S~ S03H OCH3 SO~H
in gelatin 4.0 g m.-2.
2. A stripping layer consisting of phthala-ted gelatin with a gelatin coating weight of 1.0 g.m.
3. A photosensitive silver halide gelatin emulsion layer containing 1.2 g.m. 2 silver in the form of silver chloro-bromide (70 mol% of AgCl and 30 mol~ of AgBr).
4. A supercoat layer containing gelatin 1.0 g.m.
After exposure to light behind a grey wedge, the ma-terial was processed in the dark by contacting the emul-sion side with an aluminiumised support onto which had been applied a processing composition of the following formulation:
Pyrazine 0.~ g Sulphuric acid (5N) 8.0 ml Calcium fluoride 0.1 g Hydroxyethyl cellulose 1.0 g (Natrosol type 250 HH) (trademark) Water to 100 ml After five minutes the aluminiumised support was removed. During this period the processing solution had softened the phthalated gelatin layer and when the alumin-iumised support was removed the silver halide layer and supercoat layer were removed with it to reveal a cyan image of the wedge present on the support. The density of this image was acceptably dark as a final image.
-A material as depicted in figure 15 was prepared by coating sequentially onto a 0.1 mm thick uncoloured transparent cellulose triacetate support the following layers:
1. A gelatin layer containing the same dye as used in Example 1.
2. A white reflecting layer.
3. A black opacifying layer.
4. An emulsion layer as used in Example 1.
5. A zinc powder plus carbon black opacifying layer.
6. A supercoat layer containing gela~in 1.0 g.m. 2.
After exposure to X-rays behind a lead wedge, the material was processed by immersing in a solution Or the following composition:
2-acetyl-3-methylquinoxaline 0.3 ~
Sulphuric acid 5N 8.o ml l-phenyl-5-mercaptotetrazole O.l g Water to 100 ml After three minutes a negative cyan image of the wedge was obtained which could be viewed through the support.
The zinc powder/opacifying layer used in this Example was prepared thus:
A dispersion of zinc powder in gelatin was prepared according to the following formulation:-4% gelatin solution 100 ml Sodium alkyl naphthalene sulphonate 1 ml (10% aqueous solution) Zinc powder ` 10 g 20 ml of the above dispersion were added to the carbonblack dispersion as hereinbefore described.
EXAMPI,E 3 Photographic material as shown in figure 4 was pre-pared by coating sequentially onto a 0.1 mm thick white pigmented cellulose triacetate support the layers 1-4 described in Example 1.
A~ter exposure to light behind a grey wedge 3 the material was processed in the dark by im~ersing for 1 minute in a processing solution having the following formulation:
Chromic chloride 50 g Concentrated HCl 100 ml Water to 1 litre The active metal ion ~chromous ions) was produced on shaking this solut-on with 100 g of amalgamated zinc.
During the processing period the phthalated gela~in layer was softened and on removal the silver halide layer ~as removed to reveal a cyan image of the wedge on the support. The density of this image was acceptably dark as a final image.
In a modification to the processing solution used there was included in the processing solution 0.05 g of 1-phenyl-5-mercaptotetrazole: in this case a substantial improvement in the ratio of maximum to minimum density Nas obtained.
A material as depicted in figure 15 wa~ prepared by coating sequentially onto a 0.1 mm th~ck uncoloured transparent cellulose triacetate support the following layers.
1. A gelatin layer containing the same dye as Example 3.
2. A white reflecting layer.
3. A black opacifying layer.
4. An emulsion layer as for Example 3 (conventional silver halide).
5. A zinc powder plus carbon black opacifying layer.
6. A supercoat layer containing gelatin 1.0 g.m. ~.
After exposure to X-rays behind a lead wedge, the material was processed by immersing in a solution of the ~ollowing composition: .
Chromic chloride 50 g Concentrated hydrochloric acid 700 ml Water to 1 litre After three minutes a negative cyan image of the wedge was obtained which could be viewed through the support~
The zinc opacifying layer used in the Example was prepared thus:
A dispersion of zinc powder in gelatin was prepared according to the following ~ormulation:- `
4% gelatin solution 100 ml Sodium alkyl naphthalene sulphonate .1 ml (10% aqueous solution) .Zinc powder 10 g.
20 ml of the above dispersion were added to the carbon black dispersion as hereinbefore described.
In this Example the zinc powder present in the photo-graphic material reduces the chromic chloride to chromous chloride. ~ .
A material as depicted in figure 14 was prepared by coating sequential.iy onto a 0.1 mm thick uncoloured transparent cellulGse triacetate ~upport the following layers.
- ~2 -1. A gelatin layer containing 0.2 g.m 2 of the magenta dyestuf f ~NH2 , H2N
-N = N- ~ -NH - CO - NH - ~ -N = N--OH H03S S03H HO- ~
in gelatin 4.0 g.m. 2.
2.- A white reflecting layer.
3. A black opacifying layer.
4. A silver halide emulsion layer as for Example 4 (con-ventional silver halide emulsion) 5. A supercoat layer containing gelatin 1.0 g.m. 2, After exposure to light behind a grey wedge, the material was processed in the dark by soaking for one minute in a solution of the following composition:
Vanadyl sulphate 10 ~
Water to 1 litre pH ~0.7 rollowed by contacting the emulsion side of the assembly for ? minutes with a piece of tin foil. After removal of the foil a magenta image of the wedge was obtained which could be viewed through the support.
In this Example the tin foil reduces the vanadyl sulphate to vanadous sulphate~
A material as depicted in figure lll was prepared by coating sequentially onto 0.1 mm thick uncoloured - , :
transparent cellulose triacetate support the following layers:
1. A gelatin layer containing 0.2 g.m. 2 of the magenta dyestuff of Example 5 in gelatin 4.0 g.m.~2.
2. A white reflecting layer.
3. A black opaci~ying layer~
4. A direct positive silver halide emulsion containing 1.2 g.m. 2 of silver in the form of silver chlorobromide (70 mole % AgC1 and 30 mole % AgBr).
5. A supercoat layer containing gelatin 1.0 g.m. 2.
After exposure to light behind a grey wedge, the material was proce~sed in the dark by soaking for one minute in a solution of the following composition:
Vanadyl sulphate 10 g Water to 1 litre pH 1.2 followed by contacting the emulsion side of che assembly for 2 minutes with a piece of bright iron foil. After removal of the foil a positive magenta image of the wedge was obtained which could be viewed through the support.
In this Example the iron foil reduces the vanadyl sulphate to vanadous sulphate.
The material as depicted in figure 23 was prepared by coating sequentially onto Otl mm thick uncoloured trans-parent cellulose triacetate support the following layers:-1. A gelatin layer containing 0.2 g.m. 2 of the magentaazo dye of Example 5 in gelatin 4.0 g.m. 2, 2. A white reflecting layer.
- 44 - ~
3. A camera speed direct positive silver halide emulsion containing 1.2 g.m. 2 of silver in the ~orm o~ silver ;odo-bromide (98 mole % bromide, 2 mole % iodide).
The supercoat layer was a thin ~0.004 in.) film of cellulose triacetate.
The rupturable pod contained a processing solution having the following formu]ation:-Titanium trichloride (15% solution)100 ml Diethylenetetramine pentacetic acid (DTPA) 125 ml Cas 25% solution) Potassium bromide 8 g Hydroxye~hyl cellulose 10 g Water to 1 litre pH ~.75 After exposure to light behind a grey ~ledge the mater-ial was processed by passing the assembly (in the dark) through a pair of rollers to rupture the pod and spread the processing solution. After 90 seconds the assembly was examined and a direct positive dye ;mage was visible through the support.
An aqueous solution of titanium ions in the trivalent state complexed with diethylenetetramine penta-acetic acid is stable in the absence of oxygen. Trivalent titanium ions are able to act in aqueous acid solution as a bleach-developer compound.
.. .. .
In order to produce the photographic assembl~ shown in figure 20 the following layers are applied in the liquid form to a transparent polyester support and then dried.
1. A dispersion of an aluminium powder having an average particle size of 5 ~m in gelatin, the amount applied being .
300 mg of Al/m2; the thickness of the dry layer is 2.5 ~m.
2. A gelatin solution for forming a gela~in interlayer 3 ~m thick.
3. A light-sensitive, gelatin-containing silver halide emulsion containing 30 mol % of AgBr and 70 mol % of AgCl, the weight applied being 1.2 g of Ag/m2; the layer thick-ness is 2.5 ~m.
The receiving material consists of a gelatin layer 2 ~m thick which contains 300 mg/m~ of the cyan dye o~ the formula ~ -CONH OH ,~CH3 OH NHCO- ~ -Cl - ~ N = N ~ - N = N~
K03S S03K H3CO Ko~sJ~ ~so3K
and is likewise coated onto a transparent polyester carrier.
After imagewise exposure of the record~ng material 3 the latter and a piece of the receiving material of equal size are treated for 10 seconds at 40C in the following bleach-developer solution:
H2S04 20 g (0.2 mol) Ethylene glycol monoethyl ether 300 ml 2-methyl-3-acetylquinoxaline 2.5 g (0.01 mol) NH4F 0.35 g (O.Ol mol) Water to make up to ~ 1000 ml.
The recording material and receiving material are then pressed together, the coated sides facing one another, using a pair of rollers. After 60 seconds at 30CC, the two materials are separated. The receiving material displays a dye image which is the negative of the exposure. In order to make the image stable it is then washed with water ~6 . .
for one minute.
.
After exposure 3 the material system described in Example 8 is processed in the same way with ~he bleach-developer solutions 1 to 16 in Table 1 and results similar to those of Example 8 are obtained. The bleach-developer solutions are in each case made up to 1 litre with water.
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The photosensitive portion of the photographic assembly shown in figure 20 is produced by coa~ing the following layers:
1. A dispersion of a copper powder having an a~erage part-icle size of 15 ~m in gelatin, the amount applied being 2 g of Cu/m2; the thickness of the dry layer is 3 ~m.
2. A light-sensitive gelatin-containing silver halide emulsion containing 30 mol % of AgBr and 70 mol % Or AgCl, the weight applied being 1.2 g of Ag/M2; the layer thick ness is 2.5 ~m.
The receiving material used is the material described in Example 8.
After imagewise exposure of the photosensitive portion Or the assembly the latter and a piece of the receiving material of equal size are treated for 10 seconds at 40C
in the following activator solution:
70% strength HC10l~ ~6 ml 2-Methyl-3-acetylquinoxaline 3 g Ethylene glycol monoethyl ether 40 ml Allyl alcohol 150 ml Polyethylene glycol (molecular weight 30 g 4,000) ~ater to make up to 1,000 ml.
Subsequently~ the recording material and the receiving material are squeezed together, the coated sides facing one another, using a pair of rollers. After 60 seconds at 30C the two materials are separated. The receiving material displays a dye image which is the negative of the original; In order to make the image stable, it is then washed with water for one minute.
A photographic material was produced which was similar to Example 10 but which contained, in place of copper, a brass powder having an average particle size of 10 ~m and the following elementary composition: copper 85%, zinc 14%
and aluminium 1%. Exposure and processing corresponded to Example 10, as did the resulting dye negative.
A photographic assembly as shown in figure 18 is pro-duced by applying the following layers to a transparent polyester support.
1. A gelatin layer which contains 300 mg/m2 of the magenta dye of the formula - 53 ~
P~
o o z~
:~ m 11 ~
o :Z
Q
i .. ¢~3 ,~
I
o :~:
m æ ~ 1 ~
~n ~
o ~æ ;
P~
The layer thickness is 3 ~m.
2. A gelatin layer which contains 10 mg/m2 of TiO2 in a finely dispersed form. The amount of gelatin applied is 3.5 g/m2.
3. A light-sensitive silver halide emulsion layer of the composition and thickness indicated in Example 8.
4. A gelatin layer conta;ning aluminium powder Or the same composition as in Example 8.
.
.
\ ~
- 5~ -The emulsion layer (4) is exposed imagewise through the layer containing th~ aluminium powder and subsequently is swollen at 40C for 10 seconds in the bleach-developer solu-tion according to Example 8, then stripped o~f and the remainder left to lie for 1 minute at 30C. Af'ter this time, the negative dye image has developed and is visible through the transparent support on the white background of the layer containing titanium dioxide. The image is made stable by washing with water for one minute.
Photographic material according to figure 4 is produced by applying the following layers to a white-pigmented cellu-lose triacetate support which is O.1 mm thick, 1. A gelatin layer which contains 200 mg/m2 of the cyan dye used in Example 1 in 4 g of gelatin per m2.
2. A layer of gelatin modified with phthalic anhydride was used as the strippi~g layer 3. The weight applied is 1 g/m2.
3. A light-sensitive silver halide emulsion layer which contains 1.2 g of sl;ver per m2 in the form of silver chlor-ide/bromide (70 mol per cent of silver chloride and 30 mol per cent of silver bromide).
4. A supercoat layer which contains 1 g of ~elatin per m2.
After imagewise exposure behind a grey wedge the emulsion side of the photographic material is brought into contact with an aluminium carrier to which a bleach-developer solution has been applied which contains the following components:
Pyrazine 0.2 g Sulphuric acid (5 normal) 8.o ml Calcium fluoride 0.1 g Hydroxyethylcellulo3e (thickener) 1.0 g Water to make up to . 100 ml ~ ~ ~Z~3~ ~
Contact with the aluminium carrier takes place in the dark and lasts for 5 minutes. During this time the bleach-developer solution has s~ollen the stripping layer (3).
The silver halide emulsion layer and the cover layer together with the aluminium carrier are then separated Ofr. A
cyan-coloured nega~ive image of the grey wedge in an adequate colour density is obtained on the cellulose tri acetate support.
A photographic assembly as shown in ~igure 16 was pre-~pared as follows:-A transparent cellulose triacetate support which is 0.1 mm thick is coated as follows:-1. Gelatin dye layer as in Example 13.
2. A white reflecting layer.
- 3... A black opaque layer.
4. A light-sensitive silver halide emulsion layer as in Example 6.
5. A black opaque layer which contains finely divided zinc powder.
6. A cover layer which contains 1 g of gelatin per m2.
After imagewise exposure of this material to X-rays behind a lead step wedge, the material is developed in a solution which con~ains the fol~lowing components:
2-Acetyl-3-methylquinoxaline 0.3 g.
Sulphuric acid (5 normal) 8.o ml l-Phenyl-3-mercaptotetrazole 0.1 g Water to make up to. 100 ml After 3 minutes a cyan-coloured negative image of the step wedge becomes visi~le; the image can be viewed through ~2~
the transparent support.
The layer t5) is obtained from the following d~sper-sions~
a) 4% strength aqueous gelatin solution100 ml 10% strength aqueous solution of a sodium 1 ml alkylnaphthalene sulphonate zinc powder 10 g b) gelatin . ~ g w~ter 40 ml carbon black dispersion 5 ml polyglycidyl condensation produet 2.5 ml (5% strength, aqueous) Composition ~b) is mixed for 2 minutes and stirred with 20 ml of composition (a) and the resulting mixture is then eoated as a layer.
In place of the indicated developer solution, it is also possible to use the following solution:
Chromium chloride (CrC13) 50 g Hydrochloric acid (37% strength) 100 ml Water to make up ~o 1 litre The zinc powder in layer (6) reduces th~ ~hromium~III
ehloride to chromium-II chloride.
Photographic material as`shown in Example 13 (in aec~rdance with Figure 4) is exposed imagewise behind a grey wedge and then treated for 1 minute in the dark with the following solution, which previously has also been shaken with 100 g of zinc amalgam:
Chromium chloride (CrC13) .. 50 g Hydrochloric acid (37% strength) 100 ml Water to make up to 1 litre ~z~
During this treatment time the stripping layer becomes swollen. After separating the silver halîde emulsio~ layer from the dye layer, a cyan-coloured negative image of the grey wedge in an adequate colour density is obtained.
If 0.05 g of 1-phenyl-5-mercaptotetrazole is also added to the treatment solution, a distinct improvement in the ratio of the maximum to the minimum colour density is achieved.
Photo~raphic m~terial as shown in figure 14 is produced by applying the following layers to a transparent cellulose triacetate support which is Q.1 ~m thick.
1. A gelatin layer which contains 200 mg/m2 of the magenta dye used in Example 5 in 4 g of gelatin per m2.
2. A white reflecting layer (as in Example 10).
3. A black opaque layer (as in Example 14).
4. A light-sensitive silver halide emulsion layer (as in Example 13).
5. A layer which contains 1 g of gelatin per m20 After imagewise exposure behind a grey wedge the photo-graphic material is treated in the dark for 1 minute with the following solution:
` " Vanadyl sulphate 10 g Water to make up to 1 litre (pH value of the solution 0.7) The emulsion side of the material is then brought into contact with a tin foil for 2 minutes. The tin foil reduces the vanadyl~IV sulphate to vanadium-IT sulphate. After removing the tin foil, a negative magenta image of the step .
.... .. .... . .,, _ .
`~ ~
wedge is obtained and this can be viewed trough the transparent carrier.
After exposure to X-rays behind a lead wedge, the material was processed by immersing in a solution Or the following composition:
2-acetyl-3-methylquinoxaline 0.3 ~
Sulphuric acid 5N 8.o ml l-phenyl-5-mercaptotetrazole O.l g Water to 100 ml After three minutes a negative cyan image of the wedge was obtained which could be viewed through the support.
The zinc powder/opacifying layer used in this Example was prepared thus:
A dispersion of zinc powder in gelatin was prepared according to the following formulation:-4% gelatin solution 100 ml Sodium alkyl naphthalene sulphonate 1 ml (10% aqueous solution) Zinc powder ` 10 g 20 ml of the above dispersion were added to the carbonblack dispersion as hereinbefore described.
EXAMPI,E 3 Photographic material as shown in figure 4 was pre-pared by coating sequentially onto a 0.1 mm thick white pigmented cellulose triacetate support the layers 1-4 described in Example 1.
A~ter exposure to light behind a grey wedge 3 the material was processed in the dark by im~ersing for 1 minute in a processing solution having the following formulation:
Chromic chloride 50 g Concentrated HCl 100 ml Water to 1 litre The active metal ion ~chromous ions) was produced on shaking this solut-on with 100 g of amalgamated zinc.
During the processing period the phthalated gela~in layer was softened and on removal the silver halide layer ~as removed to reveal a cyan image of the wedge on the support. The density of this image was acceptably dark as a final image.
In a modification to the processing solution used there was included in the processing solution 0.05 g of 1-phenyl-5-mercaptotetrazole: in this case a substantial improvement in the ratio of maximum to minimum density Nas obtained.
A material as depicted in figure 15 wa~ prepared by coating sequentially onto a 0.1 mm th~ck uncoloured transparent cellulose triacetate support the following layers.
1. A gelatin layer containing the same dye as Example 3.
2. A white reflecting layer.
3. A black opacifying layer.
4. An emulsion layer as for Example 3 (conventional silver halide).
5. A zinc powder plus carbon black opacifying layer.
6. A supercoat layer containing gelatin 1.0 g.m. ~.
After exposure to X-rays behind a lead wedge, the material was processed by immersing in a solution of the ~ollowing composition: .
Chromic chloride 50 g Concentrated hydrochloric acid 700 ml Water to 1 litre After three minutes a negative cyan image of the wedge was obtained which could be viewed through the support~
The zinc opacifying layer used in the Example was prepared thus:
A dispersion of zinc powder in gelatin was prepared according to the following ~ormulation:- `
4% gelatin solution 100 ml Sodium alkyl naphthalene sulphonate .1 ml (10% aqueous solution) .Zinc powder 10 g.
20 ml of the above dispersion were added to the carbon black dispersion as hereinbefore described.
In this Example the zinc powder present in the photo-graphic material reduces the chromic chloride to chromous chloride. ~ .
A material as depicted in figure 14 was prepared by coating sequential.iy onto a 0.1 mm thick uncoloured transparent cellulGse triacetate ~upport the following layers.
- ~2 -1. A gelatin layer containing 0.2 g.m 2 of the magenta dyestuf f ~NH2 , H2N
-N = N- ~ -NH - CO - NH - ~ -N = N--OH H03S S03H HO- ~
in gelatin 4.0 g.m. 2.
2.- A white reflecting layer.
3. A black opacifying layer.
4. A silver halide emulsion layer as for Example 4 (con-ventional silver halide emulsion) 5. A supercoat layer containing gelatin 1.0 g.m. 2, After exposure to light behind a grey wedge, the material was processed in the dark by soaking for one minute in a solution of the following composition:
Vanadyl sulphate 10 ~
Water to 1 litre pH ~0.7 rollowed by contacting the emulsion side of the assembly for ? minutes with a piece of tin foil. After removal of the foil a magenta image of the wedge was obtained which could be viewed through the support.
In this Example the tin foil reduces the vanadyl sulphate to vanadous sulphate~
A material as depicted in figure lll was prepared by coating sequentially onto 0.1 mm thick uncoloured - , :
transparent cellulose triacetate support the following layers:
1. A gelatin layer containing 0.2 g.m. 2 of the magenta dyestuff of Example 5 in gelatin 4.0 g.m.~2.
2. A white reflecting layer.
3. A black opaci~ying layer~
4. A direct positive silver halide emulsion containing 1.2 g.m. 2 of silver in the form of silver chlorobromide (70 mole % AgC1 and 30 mole % AgBr).
5. A supercoat layer containing gelatin 1.0 g.m. 2.
After exposure to light behind a grey wedge, the material was proce~sed in the dark by soaking for one minute in a solution of the following composition:
Vanadyl sulphate 10 g Water to 1 litre pH 1.2 followed by contacting the emulsion side of che assembly for 2 minutes with a piece of bright iron foil. After removal of the foil a positive magenta image of the wedge was obtained which could be viewed through the support.
In this Example the iron foil reduces the vanadyl sulphate to vanadous sulphate.
The material as depicted in figure 23 was prepared by coating sequentially onto Otl mm thick uncoloured trans-parent cellulose triacetate support the following layers:-1. A gelatin layer containing 0.2 g.m. 2 of the magentaazo dye of Example 5 in gelatin 4.0 g.m. 2, 2. A white reflecting layer.
- 44 - ~
3. A camera speed direct positive silver halide emulsion containing 1.2 g.m. 2 of silver in the ~orm o~ silver ;odo-bromide (98 mole % bromide, 2 mole % iodide).
The supercoat layer was a thin ~0.004 in.) film of cellulose triacetate.
The rupturable pod contained a processing solution having the following formu]ation:-Titanium trichloride (15% solution)100 ml Diethylenetetramine pentacetic acid (DTPA) 125 ml Cas 25% solution) Potassium bromide 8 g Hydroxye~hyl cellulose 10 g Water to 1 litre pH ~.75 After exposure to light behind a grey ~ledge the mater-ial was processed by passing the assembly (in the dark) through a pair of rollers to rupture the pod and spread the processing solution. After 90 seconds the assembly was examined and a direct positive dye ;mage was visible through the support.
An aqueous solution of titanium ions in the trivalent state complexed with diethylenetetramine penta-acetic acid is stable in the absence of oxygen. Trivalent titanium ions are able to act in aqueous acid solution as a bleach-developer compound.
.. .. .
In order to produce the photographic assembl~ shown in figure 20 the following layers are applied in the liquid form to a transparent polyester support and then dried.
1. A dispersion of an aluminium powder having an average particle size of 5 ~m in gelatin, the amount applied being .
300 mg of Al/m2; the thickness of the dry layer is 2.5 ~m.
2. A gelatin solution for forming a gela~in interlayer 3 ~m thick.
3. A light-sensitive, gelatin-containing silver halide emulsion containing 30 mol % of AgBr and 70 mol % of AgCl, the weight applied being 1.2 g of Ag/m2; the layer thick-ness is 2.5 ~m.
The receiving material consists of a gelatin layer 2 ~m thick which contains 300 mg/m~ of the cyan dye o~ the formula ~ -CONH OH ,~CH3 OH NHCO- ~ -Cl - ~ N = N ~ - N = N~
K03S S03K H3CO Ko~sJ~ ~so3K
and is likewise coated onto a transparent polyester carrier.
After imagewise exposure of the record~ng material 3 the latter and a piece of the receiving material of equal size are treated for 10 seconds at 40C in the following bleach-developer solution:
H2S04 20 g (0.2 mol) Ethylene glycol monoethyl ether 300 ml 2-methyl-3-acetylquinoxaline 2.5 g (0.01 mol) NH4F 0.35 g (O.Ol mol) Water to make up to ~ 1000 ml.
The recording material and receiving material are then pressed together, the coated sides facing one another, using a pair of rollers. After 60 seconds at 30CC, the two materials are separated. The receiving material displays a dye image which is the negative of the exposure. In order to make the image stable it is then washed with water ~6 . .
for one minute.
.
After exposure 3 the material system described in Example 8 is processed in the same way with ~he bleach-developer solutions 1 to 16 in Table 1 and results similar to those of Example 8 are obtained. The bleach-developer solutions are in each case made up to 1 litre with water.
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The photosensitive portion of the photographic assembly shown in figure 20 is produced by coa~ing the following layers:
1. A dispersion of a copper powder having an a~erage part-icle size of 15 ~m in gelatin, the amount applied being 2 g of Cu/m2; the thickness of the dry layer is 3 ~m.
2. A light-sensitive gelatin-containing silver halide emulsion containing 30 mol % of AgBr and 70 mol % Or AgCl, the weight applied being 1.2 g of Ag/M2; the layer thick ness is 2.5 ~m.
The receiving material used is the material described in Example 8.
After imagewise exposure of the photosensitive portion Or the assembly the latter and a piece of the receiving material of equal size are treated for 10 seconds at 40C
in the following activator solution:
70% strength HC10l~ ~6 ml 2-Methyl-3-acetylquinoxaline 3 g Ethylene glycol monoethyl ether 40 ml Allyl alcohol 150 ml Polyethylene glycol (molecular weight 30 g 4,000) ~ater to make up to 1,000 ml.
Subsequently~ the recording material and the receiving material are squeezed together, the coated sides facing one another, using a pair of rollers. After 60 seconds at 30C the two materials are separated. The receiving material displays a dye image which is the negative of the original; In order to make the image stable, it is then washed with water for one minute.
A photographic material was produced which was similar to Example 10 but which contained, in place of copper, a brass powder having an average particle size of 10 ~m and the following elementary composition: copper 85%, zinc 14%
and aluminium 1%. Exposure and processing corresponded to Example 10, as did the resulting dye negative.
A photographic assembly as shown in figure 18 is pro-duced by applying the following layers to a transparent polyester support.
1. A gelatin layer which contains 300 mg/m2 of the magenta dye of the formula - 53 ~
P~
o o z~
:~ m 11 ~
o :Z
Q
i .. ¢~3 ,~
I
o :~:
m æ ~ 1 ~
~n ~
o ~æ ;
P~
The layer thickness is 3 ~m.
2. A gelatin layer which contains 10 mg/m2 of TiO2 in a finely dispersed form. The amount of gelatin applied is 3.5 g/m2.
3. A light-sensitive silver halide emulsion layer of the composition and thickness indicated in Example 8.
4. A gelatin layer conta;ning aluminium powder Or the same composition as in Example 8.
.
.
\ ~
- 5~ -The emulsion layer (4) is exposed imagewise through the layer containing th~ aluminium powder and subsequently is swollen at 40C for 10 seconds in the bleach-developer solu-tion according to Example 8, then stripped o~f and the remainder left to lie for 1 minute at 30C. Af'ter this time, the negative dye image has developed and is visible through the transparent support on the white background of the layer containing titanium dioxide. The image is made stable by washing with water for one minute.
Photographic material according to figure 4 is produced by applying the following layers to a white-pigmented cellu-lose triacetate support which is O.1 mm thick, 1. A gelatin layer which contains 200 mg/m2 of the cyan dye used in Example 1 in 4 g of gelatin per m2.
2. A layer of gelatin modified with phthalic anhydride was used as the strippi~g layer 3. The weight applied is 1 g/m2.
3. A light-sensitive silver halide emulsion layer which contains 1.2 g of sl;ver per m2 in the form of silver chlor-ide/bromide (70 mol per cent of silver chloride and 30 mol per cent of silver bromide).
4. A supercoat layer which contains 1 g of ~elatin per m2.
After imagewise exposure behind a grey wedge the emulsion side of the photographic material is brought into contact with an aluminium carrier to which a bleach-developer solution has been applied which contains the following components:
Pyrazine 0.2 g Sulphuric acid (5 normal) 8.o ml Calcium fluoride 0.1 g Hydroxyethylcellulo3e (thickener) 1.0 g Water to make up to . 100 ml ~ ~ ~Z~3~ ~
Contact with the aluminium carrier takes place in the dark and lasts for 5 minutes. During this time the bleach-developer solution has s~ollen the stripping layer (3).
The silver halide emulsion layer and the cover layer together with the aluminium carrier are then separated Ofr. A
cyan-coloured nega~ive image of the grey wedge in an adequate colour density is obtained on the cellulose tri acetate support.
A photographic assembly as shown in ~igure 16 was pre-~pared as follows:-A transparent cellulose triacetate support which is 0.1 mm thick is coated as follows:-1. Gelatin dye layer as in Example 13.
2. A white reflecting layer.
- 3... A black opaque layer.
4. A light-sensitive silver halide emulsion layer as in Example 6.
5. A black opaque layer which contains finely divided zinc powder.
6. A cover layer which contains 1 g of gelatin per m2.
After imagewise exposure of this material to X-rays behind a lead step wedge, the material is developed in a solution which con~ains the fol~lowing components:
2-Acetyl-3-methylquinoxaline 0.3 g.
Sulphuric acid (5 normal) 8.o ml l-Phenyl-3-mercaptotetrazole 0.1 g Water to make up to. 100 ml After 3 minutes a cyan-coloured negative image of the step wedge becomes visi~le; the image can be viewed through ~2~
the transparent support.
The layer t5) is obtained from the following d~sper-sions~
a) 4% strength aqueous gelatin solution100 ml 10% strength aqueous solution of a sodium 1 ml alkylnaphthalene sulphonate zinc powder 10 g b) gelatin . ~ g w~ter 40 ml carbon black dispersion 5 ml polyglycidyl condensation produet 2.5 ml (5% strength, aqueous) Composition ~b) is mixed for 2 minutes and stirred with 20 ml of composition (a) and the resulting mixture is then eoated as a layer.
In place of the indicated developer solution, it is also possible to use the following solution:
Chromium chloride (CrC13) 50 g Hydrochloric acid (37% strength) 100 ml Water to make up ~o 1 litre The zinc powder in layer (6) reduces th~ ~hromium~III
ehloride to chromium-II chloride.
Photographic material as`shown in Example 13 (in aec~rdance with Figure 4) is exposed imagewise behind a grey wedge and then treated for 1 minute in the dark with the following solution, which previously has also been shaken with 100 g of zinc amalgam:
Chromium chloride (CrC13) .. 50 g Hydrochloric acid (37% strength) 100 ml Water to make up to 1 litre ~z~
During this treatment time the stripping layer becomes swollen. After separating the silver halîde emulsio~ layer from the dye layer, a cyan-coloured negative image of the grey wedge in an adequate colour density is obtained.
If 0.05 g of 1-phenyl-5-mercaptotetrazole is also added to the treatment solution, a distinct improvement in the ratio of the maximum to the minimum colour density is achieved.
Photo~raphic m~terial as shown in figure 14 is produced by applying the following layers to a transparent cellulose triacetate support which is Q.1 ~m thick.
1. A gelatin layer which contains 200 mg/m2 of the magenta dye used in Example 5 in 4 g of gelatin per m2.
2. A white reflecting layer (as in Example 10).
3. A black opaque layer (as in Example 14).
4. A light-sensitive silver halide emulsion layer (as in Example 13).
5. A layer which contains 1 g of gelatin per m20 After imagewise exposure behind a grey wedge the photo-graphic material is treated in the dark for 1 minute with the following solution:
` " Vanadyl sulphate 10 g Water to make up to 1 litre (pH value of the solution 0.7) The emulsion side of the material is then brought into contact with a tin foil for 2 minutes. The tin foil reduces the vanadyl~IV sulphate to vanadium-IT sulphate. After removing the tin foil, a negative magenta image of the step .
.... .. .... . .,, _ .
`~ ~
wedge is obtained and this can be viewed trough the transparent carrier.
Claims (64)
1. Process for the production of photographic images which comprises the steps of (a) imagewise exposing a photographic assembly which con-tains in order at least one silver halide emulsion layer, a layer containing a bleachable image dye or a metallic oxide and a support, (b) treating the exposed photographic assembly with an acid aqueous processing bath so as to provide in the silver halide emulsion layer or layers a solution or dispersion of a bleach-developer compound, thereby to develop the latent silver image in the silver halide emulsion(s), and (c) in the non-latent image areas allowing the bleach-developer compound to diffuse in a counter-imagewise manner from the silver halide emulsion layer(s) to the layer containing the bleachable image dye or metallic oxide and there to reduce said dye or metallic oxide.
2. A process according to claim 1 wherein the photographic assembly contains a supercoat layer.
3. A process according to claims 1 or 2 wherein the photo-graphic assembly contains one or more interlayers between each of the layers of the assembly.
4. A process according to claim 1 wherein the bleach-developer compound is in the form of a preformed solution or dispersion which is applied to the exposed photographic assembly in step (b).
5. A process according to claim 1 wherein the bleach-developer compound is in an inactive form and a solution or dispersion of this compound is contacted with a substance which renders the compound active just before or whilst the solution or dispersion is applied to the exposed photographic assembly in step (b).
6. A process according to claim 1 wherein a solution or dispersion of an inactive form of the bleach-developer compound is applied to the photographic assembly in step (b), the photographic assembly comprising either in the supercoat layer or below the supercoat layer and above the bottom-most silver halide emulsion layer a compound in layer form which renders active the inactive bleach-developer compound.
7. A process according to claim 1 wherein the bleach-developer compound is present initially in a layer in the photographic assembly in an inactive form and in step (b), a solvent for the compound is applied to the exposed photographic assembly and the thus formed solution of the inactive compound is treated in the assembly to convert the compound to the active form.
8. A process according to claim 7 wherein the solution of the inactive form of the bleach-developer compound is rendered active by bringing it into contact with a sub-stance which renders the compound active and which is also present in layer form in the photographic assembly.
9. A process according to claim 1 wherein the bleach-developer compound is in an inactive form and a solution or dispersion of this compound is subjected to electrolysis to convert the inactive compound to the active form just before or whilst the solution or dispersion is applied to the photographic assembly.
10. A process according to claim 9 wherein the photographic assembly is subjected to electrolysis at the same time or just after the solvent is applied to the assembly thereby converting the inactive form of the compound to the active form in the assembly.
11. A process according to claim 1 wherein the photographic assembly is prepared as two sections, one section com-prising the supercoat and the silver halide emulsion layer(s) and the other section comprising the layer which contains the bleachable image dye or metallic oxide and the support.
12. A process according to claim 1 wherein the photographic assembly is prepared as a single assembly which contains the supercoat, the silver halide emulsion layer(s) and the layer which contains the bleachable image dye or metallic oxide all coated on the support.
13. A process according to claim 12 wherein in the photo-graphic assembly used there is either a stripping layer or a stripping position between the silver halide emulsion layer(s) and the layer which contains the bleachable image dye or metallic oxide.
14. A process according to claim 13 wherein the stripping layer contains phthalated gelatin.
15. A process according to claim 1 wherein the silver halide emulsion is a negative working silver halide emulsion.
16. A process according to claim 1 wherein the silver halide emulsion is a direct positive silver halide emul-sion.
17. A process according to claim 1 wherein the bleachable image dye is an azo dye.
18. A process according to claim 1 wherein the bleach-developer compound is an azine compound in its reduced form and the aqueous processing bath is an aqueous acid bath.
19. A process according to claim 18 wherein the azine is pyrazine.
20. A process according to claim 18 wherein the azine is a quinoxaline compound.
21. A process according to claim 20, wherein the quinoxaline compound is substituted in the 2-, 3-, 5-, 6- and/or 7-position by lower alkyl, hydroxyalkyl or alkoxy, each of 1 to 4 carbon atoms, acylated hydroxy-methyl, amino or acylated amino, carboxyl, sulfonic acid, benzoyl, acetyl, phenyl, benzyl or pyridyl.
22. A process according to claim 1 wherein the bleach-developer compound is a metallic ion which is able to act as a silver halide developer in an acid solution.
23. A process according to claim 22 wherein the metallic ion is chromous, vanadous or titanous.
24. A process according to claim 18 wherein a non-reduced azine is contacted with a reducing agent just before or as it is applied to the photographic assembly.
25. A process according to claim 22 wherein a metallic ion in a higher valency state than the active form in an acid solution or dispersion is contacted with a reducing agent just before or as it is applied to the photographic assembly.
26. A process according to claim 24 wherein the reducing agent is a metal which in the electrochemical series is above silver and up to and including lanthanum.
27. A process according to claim 25 wherein the reducing agent is a metal which in the electrochemical series is above silver and up to and including lanthanum.
28. A process according to claim 26 or 27 wherein the reducing agent is a metal which in the electrochemical series is above silver and up to and including aluminium.
29. A process according to claim 26 wherein the metal is in the form of a metal strip.
30. A process according to claim 27 wherein the metal is in the form of a metal strip.
31. A process according to claim 29 or 30 wherein the metal strip is composed of aluminium, iron, zinc, tin or indium, or alloys which include such metals.
32. A process according to claim 26 wherein the metal is in the form of a paste coated on a base.
33. A process according to claim 27 wherein the metal is in the form of a paste coated on a base.
34. A process according to claim 32 or 33 wherein the paste contains aluminium, iron, nickel, zinc, tin or indium, or alloys which include such metals.
35. A process according to claim 18 wherein a non-reduced azine is applied as an acid solution or dispersion to the photographic assembly which contains in a layer thereof a dispersion of a metal which in the electrochemical series is above silver and up to and including lanthanum.
36. A process according to claim 22 wherein a metallic ion in a higher valency state than the active form is applied as an acid solution or dispersion to the photographic assembly which contains in a layer thereof a dispersion of a metal which in the electrochemical series is above silver and up to and including lanthanum.
37. A process according to claim 35 or 36 wherein the metal used is aluminium, copper, iron, nickel, zinc, tin, indium, gallium, lanthanum or alloys which include such metals.
38. A process according to claim 1 wherein in the photo-graphic assembly there is at least one light opaque layer adjacent to a silver halide emulsion layer.
39. A process according to claim 38 wherein there is one silver halide emulsion layer and there is a light-opaque layer on each side thereof.
40. A process according to claim 1 wherein in the photo-graphic assembly there is a white reflecting layer adjacent to the layer containing the bleachable image dye or metallic oxide on the side remote from the support.
41. A process according to claim 1 wherein the photographic assembly contains in order a supercoat layer, a light opaque layer, a silver halide emulsion layer, a light opaque layer, a layer containing a bleachable image dye or metallic oxide and a support.
42. A process according to claim 41 wherein there is pre-sent between the second mentioned light opaque layer and the layer containing the bleachable image dye or metallic oxide a stripping position or stripping layer.
43. A process according to claim 41 wherein there is present between the second mentioned light opaque layer and the layer containing the bleachable image dye or metallic oxide a white reflecting layer.
44. A process according to claim 43 wherein there is present between the second mentioned light opaque layer and the white reflecting layer a stripping position.
45. A process according to claim 1 wherein the metallic oxide is manganese dioxide or molybdenum trioxide.
46. Photographic material which contains in order a super-coat layer, at least one silver halide emulsion layer, at least one interlayer, a layer containing a bleachable image dye or metallic oxide and a support wherein there is pre-sent either in the supercoat layer or in another layer above the bottom-most silver halide layer a substance which is able to activate a non-active bleach-developer compound.
47. Photographic material according to claim 46 which contains between the supercoat layer and the silver halide emulsion layer(s) at least one interlayer.
48. Photographic material according to claim 46 or 47 wherein there is present between the silver halide emul-sion layer and the layer containing a bleachable image dye or metallic oxide a light opaque layer and/or a white reflecting layer.
49. Photographic material according to claim 46 or 47 wherein there is present between the supercoat layer and the silver halide emulsion layer a light-opaque layer.
50. Photographic material according to claim 46 or 47 wherein the substance which is able to activate a non-active bleach-developer compound is a metal which in the electro-chemical series is above silver and up to and in-cluding lanthanum.
51. Photographic material according to claim 46 or 47 wherein there is present in the material between the silver halide emulsion layer and the layer containing the bleachable image dye or metallic oxide a stripping posi-tion or stripping layer.
52. Photographic material according to claim 46 which contains a supercoat layer, a silver halide emulsion layer, a layer which contains a substance which is able to activate a non-active bleach-developer compound, a silver halide emulsion layer, a layer which comprises a bleachable image dye or metallic oxide and a support.
53. Photographic material according to claim 47 which con-tains a supercoat layer, a silver halide emulsion layer, a layer which contains a substance which is able to activate a non-active bleach-developer compound, a silver halide emulsion layer, a layer which comprises a bleachable image dye or metallic oxide and a support.
54. Photographic material according to claim 52 which con-tains between the second mentioned silver halide emulsion layer and the layer which contains the bleachable image dye or metallic oxide at least one interlayer.
55. Photographic material according to claim 53 which con-tains between the second mentioned silver halide emulsion layer and the layer which contains the bleachable image dye or metallic oxide at least one interlayer.
56. Photographic material according to claim 46 wherein there is present between the second-mentioned silver halide emulsion layer and the support a white reflecting layer.
57. Photographic material according to claim 47 wherein there is present between the second-mentioned silver halide emulsion layer and the support a white reflecting layer.
58. Photographic material according to claim 56 wherein there is present between the second-mentioned silver halide emulsion layer and the white-reflecting layer a stripping position or stripping layer.
59. Photographic material according to claim 57 wherein there is present between the second-mentioned silver halide emulsion layer and the white-reflecting layer a stripping position or stripping layer.
60. Photographic material according to claim 46 or 47 which contains either in the supercoat layer or in an interlayer above the topmost silver halide emulsion layer a bleach-developer compound in an inactive form.
61. Photographic material according to claim 46 wherein the bleachable image dye is an azo dye suitable for use in the silver dye bleach process.
62. Photographic material according to claim 47 wherein the bleachable image dye is an azo dye suitable for use in the silver dye bleach process.
63. Photographic material according to claim 61 or 62 wherein the photographic material contains a mordant layer which is capable of mordanting amine compounds released during the photographic process.
64. Photographic material according to claim 46 or 47 which contains a neutralising layer.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB48011/77 | 1977-11-18 | ||
| GB4801177 | 1977-11-18 | ||
| GB7837932A GB2007378B (en) | 1977-10-28 | 1978-09-25 | Photographic processing method |
| GB37932/78 | 1978-09-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1142014A true CA1142014A (en) | 1983-03-01 |
Family
ID=26266190
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000315741A Expired CA1142014A (en) | 1977-11-18 | 1978-11-02 | Photographic material containing a bleachable image dye or metallic oxide and a bleach-developer compound |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA1142014A (en) |
| DD (1) | DD140176A5 (en) |
-
1978
- 1978-11-02 CA CA000315741A patent/CA1142014A/en not_active Expired
- 1978-11-03 DD DD20887278A patent/DD140176A5/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| DD140176A5 (en) | 1980-02-13 |
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