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US3799780A - Process for obtaining a high contrast silver halide photographic image - Google Patents

Process for obtaining a high contrast silver halide photographic image Download PDF

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Publication number
US3799780A
US3799780A US00252014A US25201472A US3799780A US 3799780 A US3799780 A US 3799780A US 00252014 A US00252014 A US 00252014A US 25201472 A US25201472 A US 25201472A US 3799780 A US3799780 A US 3799780A
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silver halide
developer
halide photographic
high contrast
obtaining
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US00252014A
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T Suga
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Konica Minolta Inc
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Konica Minolta Inc
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Assigned to KONICA CORPORATION reassignment KONICA CORPORATION RELEASED BY SECURED PARTY (SEE DOCUMENT FOR DETAILS). Assignors: KONISAIROKU PHOTO INDUSTRY CO., LTD.
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
    • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
    • G03C5/26—Processes using silver-salt-containing photosensitive materials or agents therefor
    • G03C5/29—Development processes or agents therefor
    • G03C5/305—Additives other than developers

Definitions

  • This invention relates to a novel process for obtaining a high contrast image by treating with a lith type film developer a light-sensitive silver halide photographic material, in which the amount of silver chloride contained in the emulsion layer is less than 30 mole percent of the total silver halide.
  • a lith type lightsensitive material is treated with a high contrast developer called a lith developer or an infectious developer.
  • This developer is a hydroquinone-alkali developer having a low sulfite ion concentration and is prepared by use of formaldehyde bisulfite, hydroquinone, alkali and potassium bromide, and the lith type light-sensitive material is a photographic material containing at least 50 mole percent of silver chloride. It is well known that an image which is extremely high in contrast can be obtained when the said light-sensitive material is treated with the above mentioned lith developer.
  • a high speed type light-sensitive silver halide photographic material containing such silver halide as silver bromide or silver iodobromide gives a low contrast image when treated with the conventional lith developer, and hence has not been used to obtain a high contrast image.
  • the present invention provides a novel process for treating high speed type lightsensitive silver halide photographic materials.
  • the light-sensitive silver halide photographic material used in the present invention is entirely different in com position of silver halide from the conventional lith type photographic material, and preferably contains silver bromide or silver iodobromide.
  • the amount of silver chloride should be less than 30 mole percent of the total amount of silver halide contained therein. If the amount of silver chloride is more than 30 mole percent, fog is formed and no satisfactory image can be obtained.
  • the silver halide may be used in the form of a mixed crystal or a mixture of individual crystals. In case multilayer coating is eifected, a same or different silver halide may be incorporated into individual layers.
  • any of the known procedures may be adopted.
  • heavy metal ions as Cd++ or Pb++ may be made present at the time of crystal formation;
  • chemical sensitization as sulfur sensitization, gold sensitization or reduction sensitization may be effected, and such additives as film hardener, surfactant, stabilizer and high molecular binder may be used.
  • the developer used in the present invention is prepared by entirely removing potassium bromide from the conventional alkali developer containing hydroquinone as a sole developing agent, or removing the potassium bromide to such an extent that the amount thereof becomes less than 0.004 mole per liter of the developer, and incorporating into the developer a thiocyanate compound capable of liberating thiocyanate ion (SCN-).
  • a developer containing Metol (N-methyl-p-aminophenol sulfate) and hydroquinone as developing agents is used, the resulting image becomes low in contrast, and it is impossible to accomplish the object of the present invention, i.e. the obtainment of a high contrast image.
  • the thiocyanate compound capable of liberating thiocyanate ion may be any compound so far as it liberates thiocyanate ion (so far as it is photographically harmless).
  • Typical examples of said compound include thiocyanic acid salts of alkali metals such as K and Na, divalent metals such as Ca, Mg and Ni, trivalent metals such as Cr, and ammonium.
  • the amount of the said compound to be added is not particularly limited, but favorable results are obtained when the compound is added in an amount of less than 0.2 mole per liter of the developer used.
  • the developer contains no such bromide as potassium bromide as far as possible.
  • the amount thereof is desirably limited to such a minute amount as less than 0.004 mole per liter of the developer. In case the developer contains more than 0.004 mole of said bromide, the resulting image becomes low in contrast.
  • the developer may contain substances used in the known lith developer, e.g. a sulfite such as formaldehyde sulfite or sodium sulfite, an alkali such as sodium carbonate or sodium hydroxide, a boron compound such as borax or boric acid, and an antioxidant such as ascorbic acid.
  • the present invention is a process for developing a high speed type light-sensitive silver halide photographic material wtih an entirely novel lith developer, and this is a process capable of obtaining a high contrast which has never been attained by use of a high speed type light-sensitive silver halide photographic material.
  • EXAMPLE 1 Mixtures of alkali halides and silver nitrate were ripened at 60 C. to prepare 4 kinds of emulsions having such silver halide compositions as shown in Table l. The average particle size of each silver halide was made 0.5,u. The emulsions thus prepared were individually incorporated with sodium thiosulfate (sulfur sensitizer), subjected to chemical ripening, and then coated on a film base to prepare samples A, B, C and D.
  • sodium thiosulfate sulfur sensitizer
  • the samples A, B, C and D were individually exposed through a step wedge and then developed at 20 C. for 2 /2 minutes with each of the 3 developers shown in Table 2.
  • Norm-The developers 1:, b, and c were individually prepared by adding each of said other additives to the stock solution of the composition shown in the table.
  • EXAMPLE 2 The samples A and B prepared in Example 1 were individually developed at 20 C. for 2 /2 minutes with each of the developers d, e and 1 shown in Table 4.
  • a process for obtaining a high contrast silver halide photographic image which comprises treating, after imagewise exposure to light, a light-sensitive silver halide photographic material having a silver halide emulsion layer with a silver chloride content of less than 30 mole percent of the total silver halide with a lith-type alkali developer containing hydroquinone as a developing agent, said developer containing a thiocyanate compound capable of liberating thiocyanate ion and not more than 0.004 mole of potassium bromide per liter of the developer.
  • a process for obtaining a high contrast silver halide References Cited photographic image which comprises treating, after UNITED STATES PATENTS imagewise exposure to light, a light-sensitive silver halide 3,695,883 10/1972 Yamamoto et ah photographic material having a silver halide emulsion layer without silver chloride therein with a lith-type alkali 5 NORMAN TORCHIN, y Examiner developer comprising hydroquinone as a developing agent M. E. KELLEY, Assistant Examiner and a thiocyanate compound capable of liberating thiocyanate ion and not more than 0.004 mole of potassium 3 bromide per liter of the developer. 10

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Silver Salt Photography Or Processing Solution Therefor (AREA)
  • Photosensitive Polymer And Photoresist Processing (AREA)

Abstract

PROCESS FOR OBTAINING AHIGH CONTRAST SILVER HALIDE PHOTOGRAPHIC IMAGE, WHEREIN, AFTER IMAGEWISE EXPOSURE TO LIGHT, A LIGHT-SENSITIVE SILVER HALIDE PHOTOGRAPHIC MATERIAL HAVING A SILVER HALIDE EMULSION LAYER IS TREATED WITH A LITHTYPE ALKALI DEVELOPER CONTAINING HYDROQUINONE AS A DEVELOPING AGENT, SAID DEVELOPER FURTHER COMPRISING A THIOCYANATE COMPOUND CAPABLE OF LIBERATING THIOCYANATE IONAND NOT MORE THAN 0.004 MOLE OF POTASSIUM BROMIDE PER LITER OF THE DEVELOPER.

Description

United States Patent 3,799,780 PROCESS FOR OBTAINING A HIGH CONTRAST SILVER HALIDE PHOTOGRAPHIC IMAGE Tsuneo Suga, Tokyo, Japan, assignor to Konishiroku Photo Industry Co., Ltd.
No Drawing. Filed May 10, 1972, Ser. No. 252,014 Claims priority, application Japan, May 12, 1971, 46/ 31,141 Int. Cl. G03c 5/30 US. Cl. 96-66 R 7 Claims ABSTRACT OF THE DISCLOSURE Process for obtaining a high contrast silver halide photographic image, wherein, after imagewise exposure to light, a light-sensitive silver halide photographic material having a silver halide emulsion layer is treated with a lithtype alkali developer containing hydroquinone as a developing agent, said developer further comprising a thiocyanate compound capable of liberating thiocyanate ion and not more than 0.004 mole of potassium bromide per liter of the developer.
This invention relates to a novel process for obtaining a high contrast image by treating with a lith type film developer a light-sensitive silver halide photographic material, in which the amount of silver chloride contained in the emulsion layer is less than 30 mole percent of the total silver halide.
In the field of graphic arts, the advent of a photo graphic material capable of producing an extremely high contrast image and of a process for treating the said photographic material is desired in order that a high dot quality or a hard line image can be obtained.
In order to meet the above demand, there has heretofore been efiected a process in which a lith type lightsensitive material is treated with a high contrast developer called a lith developer or an infectious developer. This developer is a hydroquinone-alkali developer having a low sulfite ion concentration and is prepared by use of formaldehyde bisulfite, hydroquinone, alkali and potassium bromide, and the lith type light-sensitive material is a photographic material containing at least 50 mole percent of silver chloride. It is well known that an image which is extremely high in contrast can be obtained when the said light-sensitive material is treated with the above mentioned lith developer. A high speed type light-sensitive silver halide photographic material containing such silver halide as silver bromide or silver iodobromide gives a low contrast image when treated with the conventional lith developer, and hence has not been used to obtain a high contrast image.
As the result of extensive studies, I have found an en tirely novel lith developer which makes it possible to ob tain a high contrast image when used'to treat the above mentioned high speed type light-sensitive silver halide photographic material. Thus, the present invention provides a novel process for treating high speed type lightsensitive silver halide photographic materials.
The light-sensitive silver halide photographic material used in the present invention is entirely different in com position of silver halide from the conventional lith type photographic material, and preferably contains silver bromide or silver iodobromide. However, in case it contains silver chloride, the amount of silver chloride should be less than 30 mole percent of the total amount of silver halide contained therein. If the amount of silver chloride is more than 30 mole percent, fog is formed and no satisfactory image can be obtained.
Patented Mar. 26, 1974 The silver halide may be used in the form of a mixed crystal or a mixture of individual crystals. In case multilayer coating is eifected, a same or different silver halide may be incorporated into individual layers.
For preparation of the photographic material used in the present invention, any of the known procedures may be adopted. For example, such heavy metal ions as Cd++ or Pb++ may be made present at the time of crystal formation; such chemical sensitization as sulfur sensitization, gold sensitization or reduction sensitization may be effected, and such additives as film hardener, surfactant, stabilizer and high molecular binder may be used.
The developer used in the present invention is prepared by entirely removing potassium bromide from the conventional alkali developer containing hydroquinone as a sole developing agent, or removing the potassium bromide to such an extent that the amount thereof becomes less than 0.004 mole per liter of the developer, and incorporating into the developer a thiocyanate compound capable of liberating thiocyanate ion (SCN-). In case a developer containing Metol (N-methyl-p-aminophenol sulfate) and hydroquinone as developing agents is used, the resulting image becomes low in contrast, and it is impossible to accomplish the object of the present invention, i.e. the obtainment of a high contrast image. The thiocyanate compound capable of liberating thiocyanate ion may be any compound so far as it liberates thiocyanate ion (so far as it is photographically harmless). Typical examples of said compound include thiocyanic acid salts of alkali metals such as K and Na, divalent metals such as Ca, Mg and Ni, trivalent metals such as Cr, and ammonium. The amount of the said compound to be added is not particularly limited, but favorable results are obtained when the compound is added in an amount of less than 0.2 mole per liter of the developer used.
It is preferable that the developer contains no such bromide as potassium bromide as far as possible. However, if such bromide is to be made present in the developer, the amount thereof is desirably limited to such a minute amount as less than 0.004 mole per liter of the developer. In case the developer contains more than 0.004 mole of said bromide, the resulting image becomes low in contrast. In addition thereto, the developer may contain substances used in the known lith developer, e.g. a sulfite such as formaldehyde sulfite or sodium sulfite, an alkali such as sodium carbonate or sodium hydroxide, a boron compound such as borax or boric acid, and an antioxidant such as ascorbic acid.
As mentioned above, the present invention is a process for developing a high speed type light-sensitive silver halide photographic material wtih an entirely novel lith developer, and this is a process capable of obtaining a high contrast which has never been attained by use of a high speed type light-sensitive silver halide photographic material.
The present invention is illustrated in further detail below with reference to examples.
EXAMPLE 1 Mixtures of alkali halides and silver nitrate were ripened at 60 C. to prepare 4 kinds of emulsions having such silver halide compositions as shown in Table l. The average particle size of each silver halide was made 0.5,u. The emulsions thus prepared were individually incorporated with sodium thiosulfate (sulfur sensitizer), subjected to chemical ripening, and then coated on a film base to prepare samples A, B, C and D.
TABLE 1 TABLE 5 Sample AgCl AgBr .AgI Developer A- 70 30 d e f B (present invention) 100 (present invention) 97 3 5 Sample S 'y F S 'Y F S 'Y F D (present invention) 90 A 1 7 0.01 3 8 0. 4 3 3 0.3 Nora-The numeral in Table 1 shows the mole percent of individual 0 5.5 2 0.01 10 7 0.02 9 6 0. 01
silver halides.
The samples A, B, C and D were individually exposed through a step wedge and then developed at 20 C. for 2 /2 minutes with each of the 3 developers shown in Table 2.
TABLE 2 Other Developer Stock solution G. additive Mole a Formaldehyde bisulfite. 60 KBr 0.0168 b(present invention). Hydroquinone 18 KSCN 0.0168 0 (present invention) Sodium carbonate 45 NH4SCN 0.02
Norm-The developers 1:, b, and c were individually prepared by adding each of said other additives to the stock solution of the composition shown in the table.
Subsequently, the samples thus developed were subjected to sensitometry to measure the relative speeds (S), gamma values and fog values (F) of the samples. The results obtained were as set forth in Table 3.
From Table 3, it is understood that when treated with the developer a containing KBr which is a conventional developer, the sample A (conventional lith type photographic material) gives a high contrast image, whereas the samples B, C and D (high speed photographic materials used in the present invention) give low contrast images. On the other hand, when treated with the developers b and c which are used in the present invention, the sample A is markedly increased in fog and gives a halftone image, whereas the samples B, C and D are high in speed and less in fog and give high contrast images. The sample D contains 10 mole percent of silver chloride, and hence exhibits a greater increase in fog when treated with the developers d and 0, but is far less in fog than samples B and C and gives a more high contrast image than the sample A.
EXAMPLE 2 The samples A and B prepared in Example 1 were individually developed at 20 C. for 2 /2 minutes with each of the developers d, e and 1 shown in Table 4.
No'rE.The developers d, e and 1' were individually prepared by adding eatililoft other additives to the stock solution of the composition shown in e a e.
Subsequently, the samples thus developed were subjected to sensitometry to obtain the results as set forth in Table 5.
Nora-In Table 5, S, 1 and F represent relative speeds, gamma values and fog values, respectively.
From Table 5, it is understood that when the photographic material C used in the present invention is developed with the developer 1 (containing a minute amount of KBr), the gamma value is far better than in the case of the sample A.
What I claim is:
1. A process for obtaining a high contrast silver halide photographic image, which comprises treating, after imagewise exposure to light, a light-sensitive silver halide photographic material having a silver halide emulsion layer with a silver chloride content of less than 30 mole percent of the total silver halide with a lith-type alkali developer containing hydroquinone as a developing agent, said developer containing a thiocyanate compound capable of liberating thiocyanate ion and not more than 0.004 mole of potassium bromide per liter of the developer.
2. A process for obtaining a high contrast silver halide photographic image as claimed in claim 1, wherein said thiocyanate compound is selected from the group consisting of thiocyanates of potassium, sodium, calcium, magnesium, nickel and chromium and is added in an amount of not more than 0.2 mole per liter of said alkali developer.
3. A process for obtaining a high contrast silver halide photographic image as claimed in claim 1, wherein said alkali developer has the following formulation:
G. Formaldehyde bisulfite 60 Hydroquinone 18 Sodium carbonate 45 Water to make up 1 liter. KSCN 0.016'8 mole.
4. A process for obtaining a high contrast silver halide photographic image as claimed in claim 1, wherein said alkali developer has the following formulation:
G. Formaldehyde bisulfite 60 Hydroquinone 18 Sodium carbonate 45 Water to make up 1 liter. NH SCN 0.02 mole.
5. A process for obtaining a high contrast silver halide photographic image as claimed in claim 1, wherein said alkali developer has the following formulation:
G. Sodium sulfite 30 'Paraformaldehyde 7.5 Sodium bisulfite 2.2 Boric acid 7.5 Hydroquinone 22.5 Potassium thiocyanate 1.6
Water to make up 1 liter.
6. A process for obtaining a high contrast silver halide photographic image as claimed in claim 1, wherein said alkali developer has the following formulation:
Water to make up 1 liter.
5 6 7. A process for obtaining a high contrast silver halide References Cited photographic image, which comprises treating, after UNITED STATES PATENTS imagewise exposure to light, a light-sensitive silver halide 3,695,883 10/1972 Yamamoto et ah photographic material having a silver halide emulsion layer without silver chloride therein with a lith-type alkali 5 NORMAN TORCHIN, y Examiner developer comprising hydroquinone as a developing agent M. E. KELLEY, Assistant Examiner and a thiocyanate compound capable of liberating thiocyanate ion and not more than 0.004 mole of potassium 3 bromide per liter of the developer. 10
US00252014A 1971-05-12 1972-05-10 Process for obtaining a high contrast silver halide photographic image Expired - Lifetime US3799780A (en)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4230796A (en) * 1978-01-18 1980-10-28 E. I. Du Pont De Nemours And Company High speed lithographic film element
US4510229A (en) * 1981-06-26 1985-04-09 Fuji Photo Film Co., Ltd. Lithographic photosensitive material
US4598040A (en) * 1980-11-16 1986-07-01 Yoel Netz Photographic system and process
US5241398A (en) * 1990-06-26 1993-08-31 Sony Corporation Dropout compensation during track jumps
EP0732619A1 (en) * 1995-02-21 1996-09-18 Agfa-Gevaert N.V. Developing method and method for developing an exposed photographic silver halide material
US6379877B1 (en) 1995-02-21 2002-04-30 Agfa-Gevaert Method for developing an exposed photographic silver halide material

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4230796A (en) * 1978-01-18 1980-10-28 E. I. Du Pont De Nemours And Company High speed lithographic film element
US4598040A (en) * 1980-11-16 1986-07-01 Yoel Netz Photographic system and process
US4510229A (en) * 1981-06-26 1985-04-09 Fuji Photo Film Co., Ltd. Lithographic photosensitive material
US5241398A (en) * 1990-06-26 1993-08-31 Sony Corporation Dropout compensation during track jumps
EP0732619A1 (en) * 1995-02-21 1996-09-18 Agfa-Gevaert N.V. Developing method and method for developing an exposed photographic silver halide material
US6379877B1 (en) 1995-02-21 2002-04-30 Agfa-Gevaert Method for developing an exposed photographic silver halide material

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DE2222832A1 (en) 1972-11-16
GB1390960A (en) 1975-04-16

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Owner name: KONICA CORPORATION, JAPAN

Free format text: RELEASED BY SECURED PARTY;ASSIGNOR:KONISAIROKU PHOTO INDUSTRY CO., LTD.;REEL/FRAME:005159/0302

Effective date: 19871021