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
  • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
  • G03C5/26—Processes using silver-salt-containing photosensitive materials or agents therefor
  • G03C5/50—Reversal development; Contact processes
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
  • G01J5/10—Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors
  • G01J5/20—Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices

Definitions

• the present invention relates to improved developers for producing direct positive images, and more particularly relates to a method of utilizing such developers to produce direct positive images by a reversal technique utilizing only one treating bath in order to obtain reversal.
• reversal development is an involved process and involves no fewer than five essential operations: development of the latent image, bleaching and clearing to remove the developed negative silver image, exposing the remaining silver halide to light, and finally, reducing the silver halide to metallic silver in order to form the reversal image.
• operaL'ons including rinsing, hardening, fixing and washing treatments.
• photographic developing baths which produce a direct positive image without necessitating elaborate processing techniques and without the necessity for multiple treatments in rinsing baths, fixing baths, etc.
• an object of my invention to provide new photographic developers for obtaining in a single step positive black-and-white images. Another object is to provide a method for using such photographic developing baths. Still another object is to provide photographic developing baths which produce positive images in a one-bath reversal process. Other objects will become apparent from a consideration of the following description and examples.
• new photographic developing solutions which contain an alkali metal selenocyanide.
• These salts can be represented by the following general formula:
• MSeCN wherein M represents an alkali metal, such as sodium, potassium, etc.
• Example 1 Ordinary X-ray film comprising a photographic silver bromiodide emulsion coated on cellulose acetate support was exposed in the normal manner to light of the type minutes at 68 F. in a solution having the following composition:
• a medium-to-fine grain positive silver bromiodide emulsion of low gelatin content was exposed in the normal manner and then processed for 5 to 20 seconds at 95 F. in a solution having the following composition:
• Example 3 A fine-grain, slow, cine-positive photographic gelatinosilver-bromiodide emulsion was coated on a conventional cellulose acetate support and exposed in the normal manner. This film was then developed for 20 seconds at 95 F. in a solution having the following composition:
• the phenidone developer in the above developing composition can be replaced by an equivalent amount of Elon-developer, although somewhat increased silvering of the emulsion is produced by this change.
• Example 4 Another sample of the silver bromiodide emulsion described in Example 3 was processed in the developer shown in that example, except that 4 cos. of monothioglycerol were added to the developer. Addition of this material caused an increase in the maximum density with no apparent change in the image tone.
• Example 5 A fine-grain, slow, cine-positive photographic gelatinosilver-brorniodide emulsion was coated on a conventional cellulose acetate support and exposed in the normal manner. The exposed film was then'develop'ed for 20 seconds at 95 F. in a solution having the following composition:
• Phenidone developer .grarns 10.0 Sodium isoascorbate do 40.0 Sodium hydroxide do 30.0 Potassium selenocyanide do 40.0 5,;8-Dithiasuberic acid do 40.0 Monothioglycerol ml 5.0
• a reversed image having a black or blue-black tone was produced.
• the alkali metal selenocyanides used in my invention have a rather marked solvent effect on the silver halides and thus make it possible to use the developers of my invention to obtain direct positive images by the dilfusion transfer process.
• the following example will serve to illustrate this technique as applied to my new photographic developers.
• Example 6 A photographic film comprising a silver bromiodide negative emulsion coated on a cellulose acetate support was exposed in the normal manner and bathed for 6 seconds at room temperature in a solution having the following composition:
• alkali metal selenocyanide in photographic developers has been observed to occur in a variety of developers designed for use in black-and-white photography.
• These developers can comprise conventional blackand-White developers 7 including polyhydroxybenzenes (e.g., hydroquinone, chlorohydroquinone, alkylsubstituted hydroquinones, etc.), p-aminophenols, B-pyrazolidone, etc.
• S-pyrazolidones useful in the photographic developers of my invention include those described in Kendall US. Patent 2,289,367, issued July 14, 1942; Reynolds et al. US. Patent 2,743,279, issued April 24, 1956, and Allen et al. U.S. Patent 2,772,282, issued November 27, 1956, for example.
• Typical 3-pyrazolidone described by the patents include:
• the activity of the alkali metal selenocyanides useful in my invention can be varied by suitable alteration of the pH of the developing solutions. Particularly useful results have been obtained when the pH of the solution is above about 9.0. Especially useful results have been obtained at a pH of about 9.8 or higher.
• Alkaline materials suitable for use in adiusting the pH of the developing solutions are sodium hydroxide,'potasslum hydroxide, sodium carbonate, etc.
• novel developers of my invention can be used to obtain reversed images in treating many of the common photographic gelatino-silver-halide developing-out emulsions. While many of the previous methods of producmg reversal by a chemical means require the use of extremely slow, fine-grain emulsions, it can be seen from the above examples that my invention provides reversed nnages even with high-speed negative bromiodide emulsions.
• the silver halides of the photographic emulsions useful in practicing my invention can be varied and include not only the silver bromiodide emulsions illustrated in the above examples but emulsions comprising other silver halides, such as silver bromide, silver chlorobromide, silve bromiodide, silver chlorobromiodide, etc.
• Development times can vary depending upon the particular emulsion being developed, concentration of ingredients in the developer, etc.
• concentration of ingredients in the developer etc.
• the most advantageous time for a given emulsion can be determined by running a series of test strips wherein the only variable in the process is the developing time.
• the optimum concentration of ingredients for a given developer can be determined by variation of the concentration of only one of the ingredients in a given series of tests. Such matters are well understood by those skilled in the art.
• a suitable fixing paper can be made by precipitating sodium thioglyceride from a solution containing one mole of a-monothioglycerol and one mole of sodium hydroxide.
• a paper base which may be coated with a colloid layer, such as gelatin, carboxymethyl cellulose, etc., is then soaked for 30 seconds in a solution of a sodium thioglyceride and then air dried.
• the fixing paper can then be processed in contact with the photographic material with a sufficient amount of liquid between the two surfaces.
• This liquid can come solely from the developed photographic material and/ or from the wetted fixing paper.
• the fixing agent can be a different mercapto compound, such as thiobarbituric acid, ora sodium salt thereof.
• a photographic developer for producing direct positive images comprising an alkaline solution of an organic silver halide developing agent for producing black-andwhite images and from about 0.2 to about 50.0 grams per liter of solution of an alkali metal selenocyanide.
• a photographic developer for producing direct positive images comprising an alkaline solution of a polyhydroxybenzene silver halide developing agent and from about 0.2 to about 50.0 grams per liter of solution of an alkali metal selenocyanide.
• a photographic developer for producing direct positive images comprising an alkaline solution of a 3-pyrazolidone silver halide developer and fro-m about 0.2 to about 50.0 grams per liter of solution of an alkali metal selenocyanide.
• a photographic developer for producing direct positive images comprising an alkaline solution of a 3-pyrazolidone-silver halide developer, from about 0.2 to about 50.0 grams per liter of solution of an alkali metal selenocyanide and a water-soluble ascorbic acid salt.
• a photographic developer for producing direct positive images comprising an alkaline solution of hydroquinone and from about 0.2 to about 50.0 grams per liter of solution of an alkali metal selenocyanide.
• a photographic developer for producing direct posi tive images comprising an alkaline solution of hydroquinone and from about 0.2 to about 50.0 grams per liter of solution of potassium selenocyanide.
• a photographic developer for producing direct positive images comprising an alkaline solution of hydroquinone and from about 0.2 to about 50.0 grams per liter of solution of sodium selenocyanide.
• a photographic developer for producing direct positive images comprising an alkaline solution of l-phenyl- 3-pyrazolidone and from about 0.2 to about 50.0 grams per liter of solution of an alkali metal selenocyanide.
• a photographic developer for producing direct positive images comprising an alkaline solution of l-phenyl- 3-pyrazolidone and from about 0.2 to about 50.0 grams per liter of solution of potassium selenocyanide.
• a photographic developer for producing direct positive images comprising an alkaline solution of l-phenyl- 3-pyrazolidone and from about 0.2 to about 50.0 grams per liter of solution of sodium selenocyanide.
• a photographic developing solution having the following composition:
• a photographic developing solution having the following composition:
• a photographic developing solution having the following composition:
• a photographic developing solution having the following composition:
• veloping agent for reducing exposed silver halide to metallic silver, and from about 0.2 to about 50.0 grams per liter of solution of an alkali metal selenocyanide, and difiusing unexposed silver halide from said exposed photographic silver halide emulsion into said receiving layer.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)

Priority Applications (4)

Applications Claiming Priority (1)

Publications (1)

Family

ID=25265016

Family Applications (1)

Country Status (4)

Cited By (4)

Citations (3)

• 0
  • BE BE593938D patent/BE593938A/xx unknown
• 1959
  • 1959-08-14 US US833685A patent/US3021212A/en not_active Expired - Lifetime
• 1960
  • 1960-08-09 FR FR834443A patent/FR1277988A/fr not_active Expired
  • 1960-08-12 GB GB27985/60A patent/GB956368A/en not_active Expired

Patent Citations (3)

Also Published As

Similar Documents