Classifications

• • 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
  • G03C8/00—Diffusion transfer processes or agents therefor; Photosensitive materials for such processes
  • G03C8/02—Photosensitive materials characterised by the image-forming section
  • G03C8/04—Photosensitive materials characterised by the image-forming section the substances transferred by diffusion consisting of inorganic or organo-metallic compounds derived from photosensitive noble metals
  • G03C8/06—Silver salt diffusion transfer
• • 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
  • G03C1/00—Photosensitive materials
  • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
  • G03C1/492—Photosoluble emulsions

Definitions

• a high-speed, large grain gelatinosilver halide emulsion layer is made by exposing a high-speed, large grain gelatinosilver halide emulsion layer, usually on a transparent support to an original or image by means of a camera or other exposing means.
• the exposed layer is developed, fixed, washed and dried.
• a positive imagerepresenting the original scene is then obtained by exposing, usually, a slower speed small grain gelatino-silver halide emulsion layer coated on a paper support by a contact printer or with a projection enlarger to the above negative.
• the exposed element is then developed, fixed, washed and dried.
• a newer process involves either one or two elements, one'of which is a high-speed negative silver halide emulsion and the other is a so-called image receptive layer.
• the negative element is exposed in a camera in the same manner as explained above; 'but the element is processed in a special type of developer which contains a silver halide solvent.
• the exposed silver halide corresponding to the negative' is reduced to metallic silver; but at the same time, the unexposed and undeveloped silver halide migrates to the image-receptive layer, either by virtue of the fact that the negative emulsion was coated over the image receptive layer to form an integral product, or because the two elements, the image-receptive layer and the negative emulsion layer coated on separate supports are held in intimate contact during the above development.
• the image-receptive layers may be of several different types but generally comprise particles dispersed in a colloid car- ,rier, e.g., gelatin, of substances capable of catalyzing the reduction of silver halide complexes to silver. It is clear that several advantages accrue from this type of processing. Only one exposure step and one development step is High speed taking emulsions are generally large grained and have low developed-silver covering power. This, of
• a process of the invention in one of its aspects, comprises:
• a developing agent taken from the group consisting of a polyhydroxybenzene, p-aminophenol and 2,4-diaminophenol.
• At least one developing agent taken from the group consisting of a polyhydroxybenzene, p-arninophenol, 2,4-diaminophenol, p-methylaminopheno], l-phenyl-3-pyrazolidone, 1-phenyl-4-methyl-3- pyrazolidone, and ascorbic acid, and
• the process comprises:
• a developing agent taken from the group consisting of a polyhydroxybenzene, p-aminophenol and 2,4-diaminophenol,
• At least one developing agent taken from th group consisting of a polyhydroxybenzene, p-aminophenol,- 2,4-diaminophenol, p-methylaminophenol, l-phenyl-3-pyrazolidone, 1-phenyl-4-methyl-3- pyrazolidone, and ascorbic acid, and
• I outer silver halide layer is a'high-speed, large grain, low
• covering power silver halide emulsion layer containing at least80 grams of gelatin per 1.5 moles of silver halide 'and the inner silver halide emulsion layer is a hardened emulsion containing 15-80 grams, and preferably 30-60 grams of gelatin per 1.5 moles of silver halide.
• the development to form the negative image can be completed prior to the development in the presence of the silver halide solvent or the latter can take place during or subsequent to the development to form a negative image.
• the outer emulsion layer (1) can, for example, be a sensitized, gelatino-silver bromoiodide emulsion layer and the inner layer a hardened, low-speed, high covering power gelatino-silver chlorobromide emulsion layer containing not more than 80 grams of gelatin per 1.5 moles of silver halide (II) on a film, paper or other support.
• Suitable silver halide solvents include sodium, potassium and ammonium thiosulfates.
• silver transfer development may be carried out in a single step to form a silver image in (I) and a silver salt image in (II). This is then followed by washing in warm water to remove layer (I). It is essential in the single development process that the silver salt in layer (II) must be at least as soluble as the silver salt in layer (I).
• the positive silver salt image formed in layer (II) may be made visible by various means, the preferred of which is development by a fogging developer which reduces the positive silver salt image to a visible silver image. The image may also be made visible by toning or fogging, followed by conventional black and white or color coupling development.
• the process may also be carried out by developing with a low solvent developer first, followed by a second silver salt transfer developer and warm water wash off to give a positive silver salt image which may be reduced to a visible silver image as described above.
• Processing may be carried out in a tray, tank or any other conventional equipment well-known in the art.
• hydroquinone and .a silver halide solvent such as sodium thiosulfate In addition it is desirable to include either in the developer or in the top emulsion layer (I) a substance which inhibits tanning due to oxidized developer. There are many such compounds but mercapto compounds such as l-phenyl-S-mercapto tetrazole have been found suitable. Compounds such as urea and resorcinol which act as gelatin solubilizers are also suitable.
• the type of developer will depend on the type of emulsions used and the results to be obtained. For example, under certain conditions, either a positive or a negative tanned image may be obtained with a one step silver transfer development.
• EXAMPLE I A fine grain gelatino-silver chlorobromide emulsion containing 70 mole percent chloride and-3O mole percent bromide was prepared-in a conventional manner "by precipitating the silver halide in an aqueous gelatin medium by reacting soluble silver nitrate and soluble halide salts.
• the resulting emulsion which contained about 15 grams of gelatin per 1.5 moles of silver halide was freed or unwanted soluble salts formed by the precipitation reaction by washing by coagulation in the manner taught by Waller et al. U.S. 2,489,341.
• the emulsion was redispersed and without digestion or the addition of sensitizers but with the addition of a hardener and 30 g.
• Patent 2,493,748 Before coating, there was also added to the emulsion .10 gram of 1- phenyl-S-mercaptotetrazole per 1.5 mole of silver halide for the purpose of decreasing the solubility of the silver halide in the outer layer.
• the coated emulsion was then dried in a conventional manner.
• the resulting element was given a 10-second exposure through a neutral density step wedge in which the density of each step increased by the fourth root of two using a Type I-B intensity scale sensitometer equipped with a No. 2 sensitometer lamp at a scale setting of 81, a Wratten No. 79 filter at the shutter, and a white K-2 plate between the step wedge and the light source.
• the lamp was operated at an amperage of 8.5.
• the exposed element was developed under safelights for ortho sensitized film for one minute at 68 F. in the following developer.
• the element was then developed at 68 F. for two min- 'utes in a developer having the following composition.
• the room lights were turned on and the element was washed in water at about F. for A minute to remove the top emulsion layer.
• the element was then developed at 68 F. for /2 minute in the first developer above and 'washed in cold water and dried.
• the densities, read in a conventional densitometer were as follows:
• the positive characteristic curve plotted from the above data has a gamma of 18.0.
• a conventional lithographic developer having the formula:
• I film using the above type emulsion in a single coating and exposed and processed in the normal manner would have a gamma of only about 6 to 14.
• a strip of the above element was exposed as described above and developed under safelight conditions for one minute in a developer at 68 F. having the following formula:
• a sensitometric curve plotted from the above densities gave a gamma of 27.0.
• the gamma of high contrast lithographic films usually is in the range of 6 to 14, thus it can be seen that the process of the invention allows great flexibility in the selection of contrast.
• a sheet of the film was exposed through a /2 neutral density wedge in a normal manner and then through the same wedge in crossed position to a -watt lamp at Ml.
• Glacial acetic acid Potassium bromide 3M 100 Potassium ferricyanide H O, w./v.) 100 Water to make 1 liter.
• 6-nitrobenzimidazole nitrate 04 remove the top emulsion layer.
• the film was then deg gig giggggg ?f fi'f i? :III::"'::” veloped /2 minute at 68 F. in the developer for Formula Resorcinol 16.0 20 III, washed in water and dried.
• the densities of the crossed Water to make 1 liter. wedge at step 8 are shown in the following table.
• the threshold shoulder speed at a density of about 2.70 is increased by a factor of about 11.3 or by about 3 /2 camera stops by the uniform minute white light exposure at step 8 on the crossed wedge.
• EXAMPLE II A fine grain gelatino-silver chlorobromide emulsion containing 30 mole percent'bromide and 70 mole percent chloride was prepared in a conventional manner by precipitating the silver halides in an aqueous gelatin medium by reacting soluble silver nitrate and the proper soluble salts. The resulting emulsion was freed of unwanted soluble salts formed in the precipitation'reaction by washing by coagulation in the manner taught by Waller et al. U.S.
• the emulsion was made in the conventional manner and-contained l50 grams ofgelatin per 1.5 molesofsilver halide and was sensitized by digesting with an organic sulfor compound and gold chloride, all according to procedures well known to those skilled in the art.
• the coated film was dried and exposed for .08 second in the sensitometer of- Example I equipped with a V2 65' step wedge, a Corning filter 5850 plus a 0.3 neutralidensity filter with a 500-watt lamp having a color temperature of 2700 K.
• the film was developed for two minutes at 68 F. in a developer of Formula IV of Example I.
• the film was then immersed in the short stop bath of Example I for /2 minute and washed at about 125 F. to remove the unhardened silver bromoiodide negative layer.
• the film was developed in white light at 68 F. for 1 minute in a developer of Formula I of Example 1, washed and dried.
• the densities of the final positive image are given inthe following table.
• a film support was coated with the hardened gelatinsilver .chlorobromide emulsion of Example I and then overcoated with an unhardened gelatino silver bromoiodide negative type emulsion which had been optically sensitized with apanchromatic sensitizing dye.
• the coated film was given an exposure in a I-B negative sensitometer using a /2 step wedge which gave a .049 MCS exposure at step E11.
• the exposed film was processed in the same manner as Example II to give the following data in the final image.
• Example IV The film element of Example I was processed in the manner .described in :Example 11 to give the following results.
• the Processes of the Examples can be carried .out completely :under safelight :conditions by adding 2.5 grams of potassium iodide :perliter to the developer of Formula I of Example I. This serves fthepurpose of fogging the remaining silver "halide grains and the results are similar to those obtained 'by' light fogging.
• EXAMPLE V A hardened "fine grain gelatino-silver chlorobromide emulsion of the unsensitized type described in Example I but containing only grams of gelatin per 1.5 moles of silver halide was coated onzthe film support of that example to give a coating weight of about 1 16 mgJdm.
• the coated film was dried and exposed and processed .as described in Example 11 except that the first developer contained 11.7 grams of resorcinol and 200 grams of sodium thiosulfate.
• the following results in terms of densities of the final positive image were obtained as shown in the following table.
• EXAMPLE VI A film element constructed as described in Example II and exposed as described in Example II was developed for 30 seconds in developer I of Example I and having the following composition:
• Example "VI was repeated except that 10 grams of p-aminophenolwas'used in place of the p-hydroxyphenyl- .aminoacetic acid'in the second developer and the pH was adjusted to "12.1. *Seusitometric results showed that a highly useful positive image was obtained having a maximum density of 3;8, a minimum density of 0.10 and a gamma of 3.1. Processing of the exposed strip for 12 minutes only 'in asingle developer containing the p-aminophenol and the sodium thiosulfate gave a positive image having a maximum .density .of 4.0+, a minimum density of 0.09 and a gamma of 3.0.
• Example VI was repeated except that 6 grams of 2,4- diaminophenol was used in place of the p-hydroxyphenylaminoacetic acid and the pH .was adjusted to 7.3.
• the exposed strip was developed for 30 seconds in developer I of Example I and then for 10 minutes inthesolvent developer to give a good positive image having a maximum density of 2.1, a minimum density of 0.06 and a gamma of 1.0.
• Developing the strip 13 minutes in the single solvent developer gave a positive image having a maximum density of 3.2, .aminimurn density of 0.06-and a gammaof 1.3.
• Example VI was repeated except that 4 grams of ascorbic acid was used in place of the p-hydroxyphenylaminoacetic acid and the pH was adjusted to 11.7.
• the exposed strip was developed for 1 minute in developer I of Example I and 12 mniutes in the above solvent developer containing ascorbic acid to give a positive image I having a maximum density of 3.5+, a minimum density exposed and non-developed areas on top of the positive silver halide image in the under layer.
• the hydrogen peroxide bathed element as described in Example II, the residual layer in the top layer served to reinforce the positive image in the bottom layer.
• EXAMPLE X Example VI was repeated except that 6 grams of 2,4- aminophenyl and 2 grams of p-methylaminophenol were used in place of p-h'ydroxyphenylaminoacetic acid and the pH was adjusted to 7.95. Processing the exposed strip for 30 seconds in developer I of Example I and 10 minutes in the above solvent developer gave a positive image having a maximum density of 3.8+, a minimum density of .08 and a gamma of 1.7. Development of the exposed strip for 10 minutes in the solvent developer alone gave a positive image having a maximum density of 3.4, a minimum density of .08 and a gamma of 2.5+.
• the novel process of this invention provides a rapid and simple means by which silver images can be made at the highest exposure speeds of conventional negative emulsions and yet have developed silver covering powers equal to or better than the slowest fine grain conventional emulsions.
• This characteristic may be used to give either (1) higher speed, contrast and maximum density or (2) equivalent sensitomertic characteristics with less silver halide coating Weight.
• Another advantage is that large changes in sensitometric characteristics are easily obtained through simple changes in processing.
• the process of the invention provides a novel and practical means of making direct positive products having excellent sensitometric characteristics and ranging in speed from the slowest to the fastest conventional silver halide emulsions presently available.
• the process is particularly suited to those applications typical of recording films and papers which require maximum speed and contrast.
• Direct positive, high contrast graphic arts lithographic films of greatly increased speed as compared to conventional lithographic films are possible with the process of this invention.
• the novel process of the invention may also be utilized in the field of radiology, particularly in the medical X-ray field where improved sensitometric characteristics and speed are greatly desired.
• a developing agent taken from the group consisting of a polyhydroxybenzene, p-aminophenol and 2,4-diaminophenol,
• At least one developing agent taken from the group consisting of a polyhydroxybenzene, paminophenol, 2,4-diaminophenol, p-methylaminophenol, 1-phenyl-3 pyrazolidone, 1-pheny1-4- methyl-B-pyrazolidone, and ascorbic acid, and
• emulsion layers are gelatino-silver halide emulsion layers.
• outer emulsion layer is a gelatino-bromoiodide layer and the inner layer is a gelatino-brornochloride layer predominating in silver chloride.
• a developing agent taken from the group consisting of a polyhydroxybenzene, p-aminophenol and 2,4diaminophenol,
• At least one developing agent taken from the group consisting of a polyhydroxybenzene, paminophenol, 2,4-diaminophenol, p-methylaminophenol, l-phenyl-B-pyrazolidone, 1-phenyl-4- methyl-3-pyraz-olidone, and ascorbic acid, and
• emulsion layers are gelatino-silver halide emulsion layers.
• outer emulsion layer is a gelatino-bromoiodide layer and the inner layer is a gelatino-bromochloride layer predominating in silver chloride.

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• Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Inorganic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)

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• 0
  • BE BE636229D patent/BE636229A/xx unknown
• 1963
  • 1963-07-24 DE DEP32269A patent/DE1166000B/de active Pending
  • 1963-08-13 GB GB31975/63A patent/GB1061033A/en not_active Expired
• 1964
  • 1964-10-12 US US403329A patent/US3353957A/en not_active Expired - Lifetime

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