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
  • G03C7/00—Multicolour photographic processes or agents therefor; Regeneration of such processing agents; Photosensitive materials for multicolour processes
  • G03C7/28—Silver dye bleach processes; Materials therefor; Preparing or processing such materials

Definitions

• This invention relates to a method of processing photographic color pictures and more particularly to the use of furoquinoxalines and thienoquinoxalines as accelerators for dye bleach baths employed in producing dyestufi images from dyed silver images.
• the silver dye bleach-out process involves the treatment of difiusely dyed silver halide emulsions with a bleaching solution which, in cooperation with a silver image, destroys the dye at the places of said image thereby yielding dyestuif images.
• the dyes which are employed in the diifuse dyeing of the silver halide emulsion layers are primarily azo dyes or the substantive and acid type, although some basic vat dyes and alizarines may also be employed.
• the silver azo dye bleach-out process operates on the principle that the metallic silver image in cooperation with the various reagents in the bleach composition functions as the reducing agent for the azo linkage, thereby efiecting the reduction of the azo dye in situ with the silver image.
• the bleaching or decolorization of the dyestuiTs is accomplished in a bleach bath in which there occurs a simultaneous decolorization of the dye with oxidation of the metal image at the point where silver is present.
• the metallic silver is thereby converted into a silver compound which may be subsequently removed by fixation in a hypo-solution or in a solution of another silver halide solvent such as ammonium thiocyanate or a water soluble iodide such as potassium iodide and the like.
• another silver halide solvent such as ammonium thiocyanate or a water soluble iodide such as potassium iodide and the like.
• the bleach bath usually employed in this process contains an aqueous solution of a mineral acid or a mineral acid containing an alkali metal or ammonium halide such as potassium bromide, potassium chloride, potassium iodide or the cor.- responding sodium or ammonium salts.
• a mineral acid or a mineral acid containing an alkali metal or ammonium halide such as potassium bromide, potassium chloride, potassium iodide or the cor.- responding sodium or ammonium salts.
• Such baths require a relatively long treating time to ensure destruction of the dyestufis present in situ with the silver image.
• Long treatments in a bleaching solution of high acidity have the tendency to soften the gelatin of the photographic emulsion containing the silver image and bleachable dye.
• various organic compounds as catalysts to accelerate the action of such bleach baths and thereby materially reduce the bleaching time.
• furoquinoxalines and thienoquinoxalines are highly eiTective catalysts for silved dye bleach baths, that they are not 'substantive to gelatin, do not stain the gelatin layer and do not affect the quality of the final image and the employment of such compounds in this relationship constitutes the purposes and Objects of my invention.
• the furoquinoxalines and thienoquinoxalines contemplated herein are characterized by the following general formula:
• naphthene series such as benzo, naphtho, anthro
• alkoxybenzo e. g., methoxybenzo, ethoxybenzo, etc.
• lower alkylbenzo e. g., methylbenzo, ethylbenzo, etc.
• halogen substituted benzo
• thienoquinoxalines are prepared by the reaction of an o-phenylene diamine or its homologues with a 2,3-diketodihydro benzethiophene or naphthothiophene according to the method described in Berichte vol. 41, page 229 and 66, page 1223.
• mineral acid bleach bath such as hydrochloric
• tartaric, citric, boric or aryl sulfonic' acid e. g., benzene, disulfonic or naphthalene ,trisulfonic acid.
• Their action is further accelerated by the presence of' halide ions which may be added in the form of a halogen acid or in the form of a water soluble halide such as sodium, potassium,"
• the concentration of the mineral acid em'-' ployed is dependent upon'the character of the photographic color emulsion layer or layers used 1 for color film containing azo dyes.
• the concen tration of the acid may range from 5 to mls. per liter of dye bleach solution but its upper limits are controlled by the resistance of the colloidal carrier to the action of acids.
• the concentration of acid used for the treatment of photographic film containing developed azomethine and quinonimine dye images must be kept sufiiciently low to avoid their destruction by the action of acid. to 4.0 is preferred.
• the furoquinoxalines and thienoquinoxalines are water soluble, only very weakly colored, and do not stain gelatin.
• the amount employed when used as catalysts is not critical but within practical limits, an increase of concentration will increase the catalytic activity. An amount as small as 0.005 gram per liter of bleach solution will have an appreciable bleaching action on silver bearing images.
• rangin from of solubility of the catalyst in the bleach solution may be employed.
• the preferred range I is 0.005 to 1 gram per liter.
• a film containing a negative silver image and dyed uniformly with an azo dye will, upon treatment with a dye bleach solution containing a furoquinoxaline or a thiencquinoxaline, be decolorized in those places where silver images are present in proportion to the concentration of the silver. Complete decolorization or dye destruction will take place at points where considerable amounts of silver aredeposited. In the areas where little or no silver is present, little or no dye will be destroyed. The destruction will be partial and will vary with the silver density in intermediate regions. In this manner, the dye image of a character opposite to the silver image is formed. Consequently, if the silver image is negative, a positive dye image is obtained'and vice versa.
• a red-sensitive; silver halide emulsiomcontaining Dianil Blue. G (Schultz, #5114, .1931: 7th ed;,v Vol.1) was coated. on afilmhase, dried, exposed: through a transparency, white developer, shortstoppediand washed-briefly. Thesfilm strip was then. immersedior. 3 minutes in a bleach solution having. the followingzcompmsition:
• the film was washed for Z'minutes bleached; in a potassium ferricyanide-potassium bromide solution for 3 minutes, washed for 3 minutes, fixed for 5 minutes. and. finally washe'dlfor minutes and dried.
• An inspection of the driedl film strip showed that the cyan dye/had: been destroyed in proportion to the amount. of. developed silver present. Th highlight'areaswere completely clear, showed complete: removal ofthe dye and did not give any indication otresidualv stain.
• EzcampleH developed-inablaclcandi film in whichprev ious- A green-sensitive silver'halide emulsion containin Brilliant Red B (Schultz; #423) was coated on a film base and dried. The film was exposed through a color transparency; developed in a black and white developer, shortstopped'and washed for several minutes. The shortstopped' film was treated for 10 to 12 minutes in a dye bleach bath of the following composition:
• the bleached film was washed briefly, bleached in a ferricyanide bromide solution for 5 minutes, washed, fixed and finally washed again.
• Example-IV A green-sensitive silver halide emulsion containing diphenyl biguanide hydrochloride and Fast Acid Magenta (C. I. #30) was coated on a glass plate, dried and exposed through a transparency, developed in a black, and white developer, shortstopped and fixed. The fixed film was treated for 10 to 15 minutes in a dye bleach bath of the following composition:
• Example V Grams Metol 1.5 Sodium sulfite (anhydrous). 80.0 Hydroquinone 3.0 Potassium bromide. 0.5
• the developed film was then shortstopped for 3 minutes in a shortstop bath having the following composition:
• the film was then immersed for 3 minutes in a silver. dye. bleach solution. having the following composition:
• Example VI A red-sensitivesilver halide emulsion containing l-hydroxy-4-sulfo-N-stearyl-2-naphthamide as a color former for the. cyan image is dyedwith Brilliant Purpurine 10B (Schultz "1th Ed.
• emulsion is coated on a film base producing a dye emulsion thickness of approximately 7 microns and having a dye density of 1.0 at maximum absorption.
• a yellow filter Over the magenta layer is coated a yellow filter followed by a blue-sensitive silver halide emulsion layer containing 5-(4-stearylaminobenzoylacetamino)terephthalic acid as a nondifiusing color former for the yellow dye image.
• the film After exposure, the film is color developed for approximately minutes at 68 F. in the following color developer:
• the film contains negative dye and silver images in the top layer, negative magenta plus silver images and a uniform yellow azo dye in the magenta layer, and negative cyan plus silver images and a uniform reddish azo dye in the cyan layer.
• the film is washed, shortstopped and subjected to the action of a dye bleach bath having the following composition:
• the yellow and reddish azo dyes in the middle and bottom layers respectively are destroyed in situ with the negative silver images in these layers leaving a magenta negative dye printing image and a positive yellow masking image in the middle layer, and a cyan negative dye printing image and a reddish positive masking image in the bottom layer.
• the top layer contains a yellow negative dye printing image besides the silver.
• the length of time the film is treated in the bleach bath is determined by the time required to bleach the azo dyes and generally will not be sufiicient to convert all of the silver into silver salts. Therefore, a treatment with an oxidizing silver bleach bath such as a ferricyanide or copper chloride solution which may contain bromide ions is used to convert the residual silver in all layers to a silver salt soluble in hypo. Following the latter bleaching treatment, the film is fixed and washed in the usual manner.
• an oxidizing silver bleach bath such as a ferricyanide or copper chloride solution which may contain bromide ions
• Example VII materials and uses it is understood that the invention is not limited thereto, that numerous variations may be made in the procedure described herein, and that equivalent materials may be substituted.
• other color formers and other primary aromatic amino color developing agents may be used.
• azo dyes other than those specifically mentioned and utilized in the foregoing examples may be bleached satisfactorily.
• any of the generally employed processing solutions excluding the silver dye bleach bath
• any of the furoquinoxalines or thienoquinoxalines listed above may be used to replace those of the examples.
• a silver dye bleach bath comprising an aqueous solution of a water soluble halide and an acid selected from the class consisting of nonoxidizing mineral acids and water soluble organic acids and an accelerator of the general formula:
• A is an atom selected from the group consisting of oxygen and sulfur and Z and Z represent the atoms necessary to complete a carbocyclic ring system of the benzene, naphthalene, anthracene and acenaphthene series.
• a silver dye bleach bath comprising an aqueous solution of acetic acid, a halide capable of forming a silver salt of low solubility, and as an accelerator, benzofuro[2,3-b1quinoxaline.
• a silver dye bleach bath comprising an aqueous solution of acetic acid, a halide capable of forming a silver salt of low solubility and as an accelerator, benzothieno [2,3-b] quinoxaline.
• A is an atom selected from the group consisting of oxygen and sulfur and Z and Z' represent the atoms necessary to complete a car- 11 bocyclic ring system of the benzene, naphthalene, anthracene and acenaphthene series.

Landscapes

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

Priority Applications (4)

Applications Claiming Priority (1)

Publications (1)

Family

ID=23266932

Family Applications (1)

Country Status (4)

Cited By (8)

• 0
  • BE BE524877D patent/BE524877A/xx unknown
• 1952
  • 1952-12-10 US US325218A patent/US2669517A/en not_active Expired - Lifetime
• 1953
  • 1953-12-01 DE DEG13195A patent/DE941769C/de not_active Expired
  • 1953-12-09 GB GB34294/53A patent/GB736849A/en not_active Expired

Non-Patent Citations (1)

Also Published As

Similar Documents