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US3110593A - Low temperature clayden prescreening - Google Patents

Low temperature clayden prescreening Download PDF

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Publication number
US3110593A
US3110593A US69152A US6915260A US3110593A US 3110593 A US3110593 A US 3110593A US 69152 A US69152 A US 69152A US 6915260 A US6915260 A US 6915260A US 3110593 A US3110593 A US 3110593A
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US
United States
Prior art keywords
clayden
exposure
film
halftone
prescreening
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US69152A
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English (en)
Inventor
John A C Yule
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Eastman Kodak Co
Original Assignee
Eastman Kodak Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to BE610140D priority Critical patent/BE610140A/xx
Application filed by Eastman Kodak Co filed Critical Eastman Kodak Co
Priority to US69152A priority patent/US3110593A/en
Priority to DEE21441A priority patent/DE1149986B/de
Priority to GB40323/61A priority patent/GB923226A/en
Priority to FR878689A priority patent/FR1305209A/fr
Application granted granted Critical
Publication of US3110593A publication Critical patent/US3110593A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F5/00—Screening processes; Screens therefor

Definitions

  • This invention relates to the prescreening of film for use in halftone reproduction work.
  • a prescreened film' is one which has variations in sensitivity distributed in halftone pattern.
  • the present invention is based on a discovery of a relationship between the temperature of the silver halide emulsion layers and the Clayden effect.
  • Clayden sensitivity refers to the amount of desensitization produced 'by a short duration pre-exposure, and is measured in terms of the relative log exposure (low intensity, long duration) required to produce a latent image with and without the desensitization preexposure. Even films which show a very low Clayden sensitivity exhibit a much higher sensitivity at these lower temperatures. However, the present invention is concerned primarily with those materials which already show a fairly high Clayden sensitivity at room temperature, say 20 C. specifically which show at least 0.3 log E units Clayden effect to a high intensity exposure of 0.001 second at 20 C.
  • the low temperature extends the exposure time which is permissible without losing the Clayden effect.
  • one object of the invention is to provide greater scale than previously obtainable by Clayden prescreening and another object is to provide a manner of continuously Clayden prescreening.
  • Clayden effects require brief exposures, usually less than a 50th of a second. At temperatures below 10 C. the Clayden effect is still observed in a useful amount up to one second exposure time and even up to a few seconds, say four. Because of this longer duration, the use of the term Clayden effect under these circumstances might, at first sight, be questioned, but it is proper and applicable since the effect is the same, although the difference was not predicted. While the upper limit of exposure duration at room temperature is on the order of second, this upper limit increases by a factor of two for about every 10 C. drop in temperature. Dropping the temperature from +20 C. to 10 C. increases the time limit about 8 times. However, temperatures of 40 C. or lower are preferred; the drop from +20 C. to 40 C.
  • a preferred embodiment of the invention moves a chilled photosensitive layer through an exposure station synchronously with a halftone exposing image while giving an exposure of sufficiently high intensity and sufficiently short duration (in this case less than 4 seconds) to produce Clayden desensitization in a useful amount, say at least 0.6 log E units. So that the exposure station will not be impractically narrow in the direction of movement of the film and so that the film will not have to move impractically fast, an exposure lasting at least /2 second is preferable.
  • one preferred embodiment of the invention has an exposure between /2 second and 4 seconds, the film being sufficiently chilled to give Clayden effect for exposures of such duration.
  • the moving exposing image is provided either by a moving screen (ruled or contact type) with a fixed light source or by a fixed ruled screen and a moving source or exposing aperture.
  • FIG. 1 schematically illustrates one embodiment of the invention
  • FIG. 1 a silver halide emulsion layer 10 which at 20 C. will show 0.3 log E units Clayden effect to brief exposure, is carried on a support 11 which in turn rests on a metal container 12 containing Dry Ice 13 to bring the emulsion layer 10 to the temperature of Dry Ice which is about 56 C.
  • the operation must be performed in a dry atmosphere to prevent condensation of moisture on the emulsion layer 1
  • Light from a lamp 16 as indicated by arrows 17 exposes the layer 10 through a ruled halftone screen illustrated schematically at 18.
  • the exposure at the emulsion layer it at halftone distance behind the ruled screen 18 is in an undulating pattern due to the size of the source 16 and diffraction effects at the apertures in the screen 18. This is a normal halftone exposure step.
  • the Clayden desensitization in the areas-of the layer 10 which are exposed will be very high, about 1.2 to 1.6 or 1.8 log E units. This is an excellent way to get a high degree of Clayden prescreening. If the lamp to is an ordinary tungsten lamp for example the exposure may be permitted to continue for about 1 secondand the film 1% still receives a useful degree of Clayden prescreen- In FIG. 2, the ability to getClayden prescreening with relatively long duration of exposure is put to use to provide continuous prescreening.
  • a film 20, emulsion side down, is rolled from a supply roll 21 and is passed through a cooling chamber 22.
  • Chilling rollers come in contact with the emulsion or the back of the film or, as shown, with both sides of the film. These chilling rollers are kept very cold by the circulation of a low temperature liquid (say liquid air) from a supply 26 by means or" a pump 27. Alternatively the rollers may be chilled by direct contact with Dry Ice. Again the film is preferably kept in a dry atmosphere during and following chilling to the low temperature.
  • transparent roller 30 carrying a contact halftone screen 31 on the surface thereof. Lig it from a lamp 32 exposes the film while it passes from the point 33 to the point 34. A mask or reflector 35 confines the light to this area of The film is then passed over a the drum.
  • This contact halftone screen 31 on a transparent roller is similar to those used in the continuous preparation of contact halftone screen material. Projection printing is less preferable because of the added dir'liculty in obtaining suhiciently high intensity.
  • the drum or roller 33 moves relative to the mask 35.
  • the driving mechanism (which may engage the ends of the drum) is not shown.
  • the edges of the film are held by pressure rollers to an easily rotated drum and the film itself then drives the drum to insure that tl ere is no slippage between the film and the drum.
  • the main drive for the film is provided on the takeup roll by any suitable drive means, not shown.
  • a contact halftone screen in this continuous prescrcening form of the invention, but a sharp screen spaced from the film by a glass drum (or in a fiat exposure station by air) may be used.
  • the film in the case of a flat station, the film may be ctually spaced from the halftone screen with the film support in contact with rollers or t er means for maintaining the spacing of the film from therscreen.
  • the method of making a halftone sensitive material which comprises cooling to a temperature below l0 C. a photosensitive silver halide emulsion layer of the type which at C. temperature shows at least 0.3 log E units (Hayden ellect to high intensity exposures of 0.001 second, erqzosins said layer at said low temperature through a halftone screen to a high intensity, short duration, uniform exposure of suiiicient intensity and sufiiciently short duration to produce a Clayden desensitization of at least 0.6 log E units, the illumination at the emulsion being dist 'ubbed in an undulating halftone pattern.
  • E units Hyden ellect to high intensity exposures of 0.001 second, erqzosins said layer at said low temperature through a halftone screen to a high intensity, short duration, uniform exposure of suiiicient intensity and sufiiciently short duration to produce a Clayden desensitization of at least 0.6 log E units, the illumination at the
  • the method of continuously prescreening a photosensitive silver halide emulsion layer of the type which at 20 C. temperature shows at least 0.3 log E units Clayden effect to high intensity exposures of 0.001 second which comprises cooling the layer to a temperature below l0 C., moving the layer while so cooled through an exposure stationsynchron usly with a light image having an undulating halitone pattern caused by an adjacent halftone screen and exposing the layer by said image through the screen to a high intensity, short duration, uniform exposure of sufficient intensity and sufiiciently short duration to produce a Clayden desensitization of at least 0.6 log E units.
  • the halftone screen is a stationary ruled screen at halftone spacing in front of the exposure station and an illuminated area moves transversely in front of the screen so that the halftone image formed by li ht from the illuminated area in the exposure area moves synchronously with the layer.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Silver Salt Photography Or Processing Solution Therefor (AREA)
  • Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
US69152A 1960-11-14 1960-11-14 Low temperature clayden prescreening Expired - Lifetime US3110593A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
BE610140D BE610140A (de) 1960-11-14
US69152A US3110593A (en) 1960-11-14 1960-11-14 Low temperature clayden prescreening
DEE21441A DE1149986B (de) 1960-11-14 1961-07-27 Verfahren zur Herstellung von lichtempfindlichem Rastermaterial
GB40323/61A GB923226A (en) 1960-11-14 1961-11-10 Half-tone prescreened photographic material
FR878689A FR1305209A (fr) 1960-11-14 1961-11-13 Nouveau procédé pour la préparation d'un produit sensible prétramé

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US69152A US3110593A (en) 1960-11-14 1960-11-14 Low temperature clayden prescreening

Publications (1)

Publication Number Publication Date
US3110593A true US3110593A (en) 1963-11-12

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Family Applications (1)

Application Number Title Priority Date Filing Date
US69152A Expired - Lifetime US3110593A (en) 1960-11-14 1960-11-14 Low temperature clayden prescreening

Country Status (4)

Country Link
US (1) US3110593A (de)
BE (1) BE610140A (de)
DE (1) DE1149986B (de)
GB (1) GB923226A (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3504970A (en) * 1966-05-03 1970-04-07 Polaroid Corp Printing of lenticular films
US3667358A (en) * 1971-01-05 1972-06-06 William D Williams Jr Cold emulsion camera
US3775110A (en) * 1968-06-04 1973-11-27 Agfa Gevaert Ag Method for the production of lenticular elements
US3893856A (en) * 1968-06-04 1975-07-08 Agfa Gevaert Ag Method of producing geometric optical rasters

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1575408A (en) * 1923-10-04 1926-03-02 Bassani Processes Inc Method of and apparatus for making negatives from which printing plates may be produced
US2206054A (en) * 1939-01-25 1940-07-02 Du Pont Film Mfg Corp Method of forming color screens
US2211345A (en) * 1939-06-01 1940-08-13 Eastman Kodak Co Halftone screen
US2691586A (en) * 1952-06-04 1954-10-12 Eastman Kodak Co Photographic light-sensitive material for making halftones

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1575408A (en) * 1923-10-04 1926-03-02 Bassani Processes Inc Method of and apparatus for making negatives from which printing plates may be produced
US2206054A (en) * 1939-01-25 1940-07-02 Du Pont Film Mfg Corp Method of forming color screens
US2211345A (en) * 1939-06-01 1940-08-13 Eastman Kodak Co Halftone screen
US2691586A (en) * 1952-06-04 1954-10-12 Eastman Kodak Co Photographic light-sensitive material for making halftones

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3504970A (en) * 1966-05-03 1970-04-07 Polaroid Corp Printing of lenticular films
US3775110A (en) * 1968-06-04 1973-11-27 Agfa Gevaert Ag Method for the production of lenticular elements
US3893856A (en) * 1968-06-04 1975-07-08 Agfa Gevaert Ag Method of producing geometric optical rasters
US3667358A (en) * 1971-01-05 1972-06-06 William D Williams Jr Cold emulsion camera

Also Published As

Publication number Publication date
GB923226A (en) 1963-04-10
DE1149986B (de) 1963-06-06
BE610140A (de)

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