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
  • G03C1/00—Photosensitive materials
  • G03C1/52—Compositions containing diazo compounds as photosensitive substances

Definitions

• Patented a 12, 1937 METHOD OF MAKING NEGATIVE PRINTS Jan Hendrik de Boer and Roelo! Jan Hendrik Alink, Eindhoven, Netherlands, assignors to N. V. Philips Gloeilampenfabrieken, Eindhoven,
• the present invention has for its object to provide an improved method for obtaining negative photographic prints by self-developing layers sensitized by means of a diazonium compound.
• the expression self-developing layer is to mean herein a layer whereon colored material is formed by the reaction of the light decomposition l5 productof the diazonium compound, which decomposition product remains in the material and which, by reaction'with the diazonium compound still present in the material, forms a colored compound.
• the photochemical decomposition of a diazonium compound results in the formation of a corresponding phenol; the Nzx-group being replaced by the OH- group.
• This replacement may take place not only 5 photochemically, but also otherwise, for instance,
• the hydroxy-compound formation caused by photochemical decomposition would start to form colored material with the diazonium compound not yet decomposed, and on the nonexposed portions the diazonium compound would be hydrolyzed and decomposed and the resulting hydroxy-compound would also form colored material with the diazonium compound not yet decomposed.
• Such hydrolysis and correspondingdecomposition is accelerated by the usual after-treatment in developing such prints, which consists in their exposure to a moist atmosphere, possibly with simultaneous heating of same.
• the present invention is based on the recognition of the above and consists of a method by means of which negative photographic prints are obtained with self-developing layers which are sensitized by means of a diazonium compound.
• Such layers are subjected to a moderate actinic exposure and the fixing of the negative image is achieved by bringing about a decomposition by hydrolysis of the diazonium compound at such portions of the layer which are not struck by light, the decomposition being accompanied by the liberation of nitrogen.
• moderate actinic exposure is meant an exposure which, with the sensitized material, lays the basis for the formation of a negative image.
• the subjecting oi the actinicaliy-exposed layer to the moisture normally present in the atmosphere as a rule sufices.
• the process may be accelerated by insuring an ample supply of water vapor during the application of heat.
• Suitable methods to combine heat and moisture treatments are, for instance, to subject the photochemically-exposed layer to hot ironing under a damp cloth, or to pass it through heated calenders covered with damp cloth.
• Such diazonium compounds which readily hydrolyze and decompose are especially suitable to practice the invention. Especially good negatives are obtained if the sensitized layer also contains a copper salt.
• the sensitized material for instance sensitized paper or linen
• intense drying for instance, by drying it in a flow of gas which has been previously dried by means of P205, or in a fiow of gas from which the moisture has been frozen out by cooling the gas to a low tempera-- ture, and by providing means to preserve the intense dry state of the sensitized material during its storage.
• Example I A paper carrier is treated on one side with an aqueous solution of 2% of 1-hydroxy-2-diazonium benzene-l-sulphonic acid and 2.7% of Cu(NO3)z6HzO and is then exposed for 25 sec. under a positive drawing, for instance, under a tracing drawn on transparent linen, at a distance of 50 cms. from a 5 kilowatt incandescent lamp, so that the diazonium compound falling under the non-transparent portions of the drawing receives practically no light, whereas the remaining portions are subjected to a .moderate actinic exposure.
• a positive drawing for instance, under a tracing drawn on transparent linen, at a distance of 50 cms. from a 5 kilowatt incandescent lamp, so that the diazonium compound falling under the non-transparent portions of the drawing receives practically no light, whereas the remaining portions are subjected to a .moderate actinic exposure.
• the exposed paper is developed and fixed by allowing it to remain for 3 days at ordinary temperatures in a chamber which is shut oil from daylight and which is saturated with water vapor. Thereby a negative photographic print in a dark-blue tinge is produced. 0n the non-exposed portions the sensitized material is decomposed and practically no formation of colored material takes place thereon.
• Example II The paper, after being sensitized and actinically exposed in accordance with Example I, is subjected in the dark for about half an hour at ordinary temperatures, to an atmosphere satmated with moisture; after this it is passed for 2 minutes under a damp cloth at a. temperature of 100 C. The result is a brown-violet negative photographic print.
• the so-sensitized paper is then exposed for 10 sec. under a drawing provided on transparent linen at a distance of 25 cms. from a 5 kilowatt incandescent lamp.
• the exposed paper is allowed to remain for-15 minutes in an oven heated to a temperature of C.
• air is blown which is saturated with water vapor at a temperature of 75 C. The result is a darkblue negative photographic print.
• the portions are slightly grey colored.
• Example IV The sensitized material of Example III, after being exposed as stated above, is kept for 24 hours in a dark medium, which at ordinary temperatures has been saturated with water vapor. Subsequently the material is subjected to hot-ironing for 2 minutes under a damp cloth at a temperature of C. The result is a dark-blue negative photographic print.
• Example V that a developed and fixed negative photographic print having a brown tinge is obtained.
• the steps of forming on a carrier a light-sensitive layer by applying thereto a solution of about 40 grams of 2-diazonium-1-hydroxy-5-methylbenzene-4-sulphonic acid and 100 grams of Cu(NO:)2.6H2O in 1 litre of water, drying the so-treated carrier, subjecting the carrier to a moderate actinic exposure to decompose part of the diazonium compound at selected portions of the layer, and circulating over the exposed layer in the absence of actinic light for about 15 minutes air at a temperature of about C. and saturated with water vapor at a temperature of about 75 C., to thereby develop and fix the negative image without the addition or removal of any substance other than nitrogen and to completely decompose the diazonium compound present on the unexposed portion of the layer.
• the steps of forming on a carrier a light-sensitive layer by applying thereto a solution of about 40 grams of 2-diazonium-1-hydroxy-5-methylbenzene-4-sulphonic acid and grams of Cu(NO3)z.6I-I2O in 1 litre of water, drying the carrier, subjecting the carrier to a moderate actinic exposure to decompose part of the diazonium compound at selected portions, and placing the layer for about 24 hours in a darkened atmosphere saturated with water vapor and at substantially room temperature, and then hotironing the carrier for about 2 minutes beneath a damp cloth at a temperature of about 100 C., to thereby develop and fix the negative image without the addition or removal of any substance other than nitrogenand to completely decompose the diazonium compound on the unexposed portions of the layer.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Non-Silver Salt Photosensitive Materials And Non-Silver Salt Photography (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=6506671

Family Applications (1)

Country Status (4)

Cited By (5)

• 0
  • BE BE407031D patent/BE407031A/xx unknown
• 1934
  • 1934-11-21 GB GB33490/34A patent/GB434761A/en not_active Expired
  • 1934-12-19 US US758333A patent/US2095408A/en not_active Expired - Lifetime
  • 1934-12-28 FR FR783415D patent/FR783415A/fr not_active Expired

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