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
  • G03C5/16—X-ray, infrared, or ultraviolet ray processes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S430/00—Radiation imagery chemistry: process, composition, or product thereof
  • Y10S430/167—X-ray
  • Y10S430/168—X-ray exposure process

Definitions

• This invention relates to a process for the production of color radiographs as well as to a light-sensitive material for performing the said process.
• a major disadvantage of the silver halide emulsions used for such radiographic materials is their low sensitivity with respect to X-rays or similar radiation. Only films of highest possible sensitivity and thus of low resolving power are consequently considered to be suitable for the instant purpose.
• Another disadvantage of X-ray exposures is caused by the low differences in the transparencies of the different parts of the objects to the X-rays. This leads to low contrasts in the resulting radiographic image.
• the relatively thick emulsion layers necessary for producing a negative having a sufficient contrast reduce considerably the distinctness or clarity of the details of the resulting image.
• the same disadvantageous etfect is caused by the intensifier foils used for increasing the sensitivity.
• the objects of the invention can be attained by using a film material comprising a support and two light-sensitive silver halide emulsion layers containing dilferent color couplers which yield dyestuffs of different color by de velopment with a suitable color-forming primary aromatic amine developer.
• the two layers can be arranged one above the other on the same side or separately, one on each of the two sides of the support.
• Such a material can be built up, for example, as follows:
• a support consisting, for example, of a cellulose ester such as a cellulose acetate or cellulose nitrate film, a polycarbonate, particularly a polycarbonate of a bis(hydroxyphenyl)alkane, a polyester derived from ethylene glycol and terephthalic acid, paper or glass, is coated with a silver halide emulsion layer that is sensitized to yellow light containing a cyan color coupler. Above this layer is cast another silver halide emulsion layer that is not additionally sensitized containing a red color coupler.
• the imagewise exposure of the film material is effected in conventional manner, for example, by means of X-rays.
• the sensitivity of the material can be increased in conventional manner by the use of luminescent screens or by fiuorescing substances embedded in the emulsions or by intensifier foils.
• the exposed material is developed in conventional manner by means of a color-forming primary aromatic amine developer, for example, in accordance with the general procedure of the Agfacolor negativepositive process. Thereafter the developed material containing congruent silver and dyestufi images is subjected to a second, non-imagewise exposure to light of the yellow region of the visible spectrum. This is preferably performed by exposing the film through a yellow filter, for example, the Agfa dark-room filter 112 or the Agfa Repro color separation filter L4.
• the second exposure is followed by a second development. Further processing of the exposed and developed material is performed in accordance with common practice, whereby a two-colored radiograph is obtained.
• the object of the subsequent non-imagewise exposure with yellow light is to expose the yellow-sensitive layer at the areas which have remained unexposed during the imagewise exposure.
• the unsensitized layer exposed to light during the first exposure remains unaffected by the subsequent non-imagewise exposure with yellow light.
• the silver and dyestuff images of the first imagewise exposure which are formed in this layer during the first development act as a black filter at the subsequent exposure to yellow light and prevent a second exposure of the yellow-sensitive layer at the areas which had been affected by the first imagewise exposure.
• the layers of different sensitivity and containing different color couplers are arranged separately on the two sides of the support.
• a subsequent influencing of the two-colored layers is possible.
• the subsequent exposure when using this material is of course effected from the side of the film where the silver halide emulsion layer insensitive to the light rays of the subsequent exposure is arranged.
• Example 1 A transparent cellulose acetate foil provided with a subbing layer is coated with a silver chloride gelatin emulsion which is panchromatically sensitized and contains 10 g. of the sodium salt of l-hydroxy-Z-naphthoylamino-4'-(methylheptadecylamino)benzene 3' sulfonic acid having Formula I hereinafter, per kilogram.
• a silver bromide gelatin layer which is not additionally sensitized containing 10 g. of N-(Z-methyloctadecylamino-S-carboxyphenyl) 4 hydroxyethoxybenzoylacetamide having the Formula II hereinafter, per kilogram.
• Said film is exposed to X-rays in conventional manner by interposing the object to be radiographed between said film and the X-ray source.
• the exposed film is developed by means of an alkaline developer containing N ,N-dirnethylphenylene diamine as the color-forming developer compound at 20 C. for 8 minutes.
• the second exposure is accomplished through a yellow filter (Agfa Repro color separation filter L4exposure time 30 seconds). Thereafter it is developed again in a developer described above. Finally the developed film is bleached and fixed after washing and drying.
• the resulting radiograph shows a yellow dyestulf image of the object.
• the background of the image has a cyan color.
• Example 2 A transparent foil formed of a polycarbonate of a his- (hydroxyphenyl)alkane is coated on one side with a silver chloride gelatin emulsion layer containing the cyan coupler represented by Formula I hereinbefore in Ex ample 1. The opposite side of the support is coated with a silver bromide gelatin emulsion layer which is not additionally sensitized containing g. of w-(p-dodecylaminobenzylidene)-w-cyano-acetone having Formula III hereinafter and 10 g. of the sodium salt of dodecyl sulfate (C H OSO Na). The film is processed as described in Example 1 whereby the second exposure with yellow light is effected from the side of the film carrying the silver bromide emulsion layer. A magenta image on a cyan colored background is obtained.
• the chemical structure of the color coupler to be used is not especially critical but is selected according to the requirements of the particular radiographic process.
• the development can be performed with any colorforming developer, for instance, a primary aromatic amine developer.
• the subsequent exposure may be performed with any colored light of the visible spectrum for which one of the silver halide emulsions has been sensitized and can be performed during or after the first development. Bleaching and fixing of the developed film is performed in conventional manner.
• process for producing a colored radiograph with X-rays comprising (a) exposing to said rays a light-sensitive radiographic material comprising two light-sensitive silver halide emulsion layers supported on a transparent supporting layer, the top emulsion layer of which contains no additional sensitizer and the lower emulsion layer is sensitized to yellow light, each of the emulsion layers being sensitized to different regions of the spectrum and containing different color couplers which upon development form dyestuffs of different color;
• the lightsensitive radiographic material comprises a transparent supporting layer and two light-sensitive silver halide emul- References Qited by the Examiner UNITED STATES PATENTS 2,098,442 11/1937 Troland 9694 2,403,722 7/1946 Jelley et al. 9627 2,705,200 3/1955 Tulagin 9674 2,994,610 8/1961 Maus et al. 96100 2,997,388 8/1961 Blanchard 9674 3,035,913 5/1962 Hellmig 9674 3,114,833 12/1963 Fine 96-74 FOREIGN PATENTS 543,606 3/ 1942 Great Britain. 562,854 7/1944 Great Britain.

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

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Cited By (2)

Citations (9)

• 0
  • BE BE614897D patent/BE614897A/xx unknown
• 1961
  • 1961-03-10 DE DEA36927A patent/DE1135754B/de active Pending
• 1962
  • 1962-03-08 GB GB8964/62A patent/GB935050A/en not_active Expired
  • 1962-03-08 US US178252A patent/US3235728A/en not_active Expired - Lifetime

Patent Citations (9)

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