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
  • G03C5/29—Development processes or agents therefor
  • G03C5/305—Additives other than developers
  • G03C5/3056—Macromolecular additives

Definitions

• Photographic films used in the graphic arts for making half-tone or line images should be capable of producing extremely high contrast and good image sharpness. These factors contribute in the case of half-tone images to high dot quality, that is, to the production of halftone dots of high density and sharpness.
• the photographic developers intended to produce high contrast images do not produce the high contrast desired, or if they produce high contrast images are deficient in tray life, that is, resistance to aerial oxidation.
• a further object is to provide a photographic developer capable of giving high contrast and at the same time having good aeration life.
• a still further object is a photographic developer capable of producing half-tone images of good dot quality.
• an exposed photographic silver halide emulsion especially an emulsion designed for producing a high contrast image
• a solution of a p-dihydroxybenzene developing agent containing a polyalkyleneglycol less than about 5 grams per liter of any dissociated sulfite and substantially no aminobenzene developing agent.
• relatively large quantities of an un-ionized sulfite such as sodium formaldehyde bisulfite, may be present.
• Our invention comprises in its broader aspects the use of a hydroquinone or substituted hydroquinone developing agent in a developing solution containing a polyalkylene glycol, especially a polyethylene glycol or one of its derivatives as hereinafter described, the solution being of low sulfite content, that is, containing less than 5 grams per liter of any sulfite.
• the solution should also be free of aminobenzenedeveloping agent such as the N-methyl-p-aminophenol commonly used.
• Photographic emulsions designed for producing high contrast images such as Kodalith films (see Kodak Graphic Arts Films and Plates, Eastman Kodak Company, 1951) produce images having a gamma of 9 to 10 and half-tone dots of good qualitywhen developed in a suitable developing solution.
• Kodalith films see Kodak Graphic Arts Films and Plates, Eastman Kodak Company, 1951
• Our developing solutions contain a p-dihydroxybenzene developing agent such as hydroquinone, toluhydroquinone, 2,5 dimethylhydroquinone, 2,5 diethylhydroquinone, etc., but are substantially free of aminobenzene developing agent such as p-aminophenol, N-methyl-paminophenol, p-phenylenediamine, etc.
• a p-dihydroxybenzene developing agent such as hydroquinone, toluhydroquinone, 2,5 dimethylhydroquinone, 2,5 diethylhydroquinone, etc.
• aminobenzene developing agent such as p-aminophenol, N-methyl-paminophenol, p-phenylenediamine, etc.
• Our developers should contain little or no sulfite preservative, that is, sodium sulfite, sodium bisulfite, potassium metabisulfite, tc. While this sulfite compound need not be entirely excluded from the developer its contents should not be greater than about 5 grams per liter of solution.
• the polyalkyleneglycol or alkylene oxide polymers used in the developing solution are polymers derived from alkylene oxides containing from 2 to 4 carbon atoms, e.g., ethylene oxide, propylene oxide and butylene oxide.
• alkylene oxides containing from 2 to 4 carbon atoms e.g., ethylene oxide, propylene oxide and butylene oxide.
• the preparation of polymers from these compounds is described in Ellis, The Chemistry of Synthetic Resins (1935), page 990 to 994.
• Various derivatives of alkylene oxides may also be used in the developing solution, e.g., condensation products of alkylene oxide with glycols such as those having from 8 to 18 carbon atoms as described in U.S. Patent No.
• Carbowax 1500 Polymers having a molecular weight of about 1000 and above are solids and are more easily handled. These compounds are sold by Carbide and Carbon Chemicals Corporation under the trade name Carbowax, e.g., Carbowax 1500, Carbowax 4000, Carbowax 6000, the numerals usually indicating average molecular weight. Carbowax 1500, however, has an average molecular weight between 500 and 600.
• alkylene oxide polymers which we may employ:
• Polyethyleneglycol 400 Polyethyleneglycol 600 Polypropyleneglycol 425 Polyglycol E-IOOO Polyglycol E-4000 Polyglycol E9000 (These compounds are sold by Carbide and Carbon Chemicals Corporation and are believed in the case of the ethylene oxide polymers to have the general formula HOCH CH O (CH O CHgCHgOH Our invention will. now be more specifically illustrated (made by condensing 1 approximately 15 moles of by reference to the following examples:
• This developer had a pH of 10.1.
• Strip 10/i Speed Gamma Fog Example 2 An emulsion similar to that used in Example 1 was exposed in the same way, a half-tone screen being inan alkylene oxide polymer selected from the class consisting of (1-) condensation productsof alkylene oxide with glycols, and (2) condensation products of an alkylene oxide with aliphatic compounds se- 5 lected from the class consisting of aliphatic monohydric alcohols, aliphatic monobasic acids, aliphatic monoamines and monohydric phenols,
• said alkylene oxide containing from 2 to 4 carbon atoms and said alkylene oxide polymer having a molecular weight of at least 400, and said developer containing susbtantially only said p-dihydroxybenzene developing agent as developing agent for silver halide.
• a photographic developer capable of producing high contrast images upon photographic development comprising a. developing solution containing a p-dihydroxybenzene developing agent,
• Sodlun ⁇ sulfite (fieslccated) 4.
• the p-dihydroxy- W K bromlde benzene developing agent is hydroquinone
• the polyethylsodlum blcarbonate eneglycol is the oleyl ether of polyethyleneglycol
• the Sodlum carbmate monohydrate 22 dissociated sulfite is sodium sulfite in an amount of about Water to 1 hter- 2.5 grams per liter, the developer being free of other sulfite.
• De pe 5 the p-dihydroxy- W K bromlde benzene developing agent is hydroquinone
• the polyethylsodlum blcarbonate eneglycol is the oleyl ether of polyethyleneglycol
• the Sodlum carbmate monohydrate 22 dissociated sulfite is sodium sulfite in an amount of about Water to 1 hter- 2.5 grams per liter, the developer being free of
• the method of developing a high contrast photo - t 3 fi$$ gfifi ii Gamma E EE graphic image in an exposed silver halide emulsion layer v r which comprises developing said exposed emulsion layer 1 in a photographic developer containing.
• alkylene oxide polymer selectedfrom the class, con- Y 7 sisting of (l) condensation products of alkylene 1 03mm 4000 2 1%. gig "g oxide with glycols, and (2) condensation products 7 J of an alkylene oxide with aliphatic com ounds se- .ii "i; lected from the class consisting, of aliphiitic mono- 1 ML Carbowax 6000 3 228. g g f hydric alcohols, aliphatic monobasic acids, aliphatic 5 .880 14.1 9 monoamrnes and monohydnc phenols, 1 cc.
• [1 muryl amine of Cap 5 23 8 said alkylene oxide containing from 2 to 4 carbon bownx 1500 4 .270 14.2 atoms and said alkylene oxide polymer having a g 328 1%; g molecular weight of at least 400, and said developer containing substantially only said p-dihydroxyben-
• dot quality is indicated by a scale of 1 iz g g agent as developmg agent for Sflver to 9 in which 1 is the poorest quality and 9 is the highest uality as determined by visual inspection.

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Cited By (7)

Citations (3)

• 1958
  • 1958-03-07 FR FR1209925D patent/FR1209925A/fr not_active Expired
  • 1958-03-10 GB GB7692/58A patent/GB874078A/en not_active Expired
• 1962
  • 1962-02-09 US US172097A patent/US3158483A/en not_active Expired - Lifetime

Patent Citations (3)

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