Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2001-11-28
2003-08-19
Letscher, Geraldine (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S139000, C430S966000, C430S570000, C430S581000, C430S585000, C430S588000, C430S603000, C430S604000, C430S605000
Reexamination Certificate
active
06607876
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a silver halide photographic light-sensitive material and, more particularly, to a silver halide photographic light-sensitive material containing tabular silver halide grains for use in a radiographic film materials and screen-film combinations thereof.
BACKGROUND OF THE INVENTION
Combinations of intensifying screens provided with luminescent phosphors and light-sensitive silver halide photographic materials are conventionally used for medical diagnosis. By X-ray radiation the luminescent phosphors in the screen panel or panels are converting X-rays into visible radiation, thereby exposing the film material in contact with the said panel (for single-side coated materials as e.g. in mammography) or panels (for duplitized materials as e.g. in chest imaging).
It is clear that in order to get an image to be examined on the film that after said exposure the film material is processed in a wet processing cycle, requiring appropriate chemistry. A normal processing cycle, whether or not performed in an automatic processing machine, is following the steps of developing, fixing, rinsing an drying. The more film material is passing in the corresponding processing solutions of developer and fixer, the more both of them become exhausted. In order to overcome that problem replenishing is required.
As nowadays ecology becomes more and more important it is recommended to reduce amounts of processing chemicals (developer, fixer and corresponding replenishers) to a considerable extent in order to reduce waste chemicals. Within the same context it is recommended to reduce wash out or rinsing out of chemical compounds coated in the film material as e.g. wash out in the processing of sensitizing dyes or filter dyes present in hydrophilic layers of the said film material thereby causing deposition of dirt on the walls and rollers of the processing tanks.
Especially when the light-sensitive silver halide emulsion crystals have been made sensitive to visible light as e.g. to blue or green light emitted from blue light or green light emitting intensifying phosphor screens the corresponding spectral sensitizers and optionally present filter or antihalation dyes make arise the problem of insufficient removal from the film material, thereby causing residual color making increase minimum density and deviate image tone from the desired outlook of the processed image.
Silver bromide emulsion crystals have an absorption spectrum which is shifted towards longer wavelengths of the radiation spectrum if compared with silver chloride emulsion crystals the spectrum of which is shifted more to the ultraviolet range. Luminescent phosphors however are not completely matching the absorption spectra of non-spectrally sensitized emulsion crystals so that spectrally sensitizing dyes are required in order to provide, after processing of the (preferably forehardened) photographic material, an image having a suitable gradation, high covering power and low cross-over (leading to a high sharpness) as has e.g. been recommended in U.S. Pat. Nos. 4,414,304; 4,425,425 and 4,425,426 in order to make use of emulsion crystals or grains having a tabular habit and a high aspect ratio. As this application technique makes improvement of covering power of silver halide possible, it is desired in view of saving silver. Said advantage of silver saving, expressed as a lower coating weight, is the more preferred as rapid processing applications are required, which is nowadays an ever more returning demand.
Attaining the required sensitometry, particularly speed, even in a rapid processing cycle of at most 90 seconds, making use of minimum amounts of replenisher solutions of developer and fixer, and further getting an image having the desired contrast, high definition, covering power and image tone (the improvement of which has e.g. been demonstrated in EP-A 0 770 909, wherein use has been made of a specific multi-layer arrangement with grains having a cubic crystal habit located farther from the support without showing disturbing residual coloration) remains an ever lasting demand.
Besides the disadvantage of providing a brownish image tone as becomes more stringent for thinner tabular grains or crystals, light-sensitive materials making use of tabular silver halide grains are susceptible to changes in development processing conditions. Therefore, application of thin tabular grains in silver halide photographic materials requires additional research in order to make those materials less dependent on the said development processing conditions, more particularly with respect to sensitometry, covering power and image tone as these are still not completely satisfactory.
OBJECTS OF THE INVENTION
It is, therefore, an object of the present invention to provide a silver halide photographic light-sensitive material containing thin tabular silver halide grains which is improved with respect to dependence of photographic properties on development processing conditions, and, more particularly, with a reduced dependence of covering power and image tone on the said development processing conditions.
Further it is an object of the present invention to provide a silver halide photographic light-sensitive material containing tabular silver halide grains which is improved with respect to dye stain (residual color), thus preventing said stain from appearing onto the photographic light-sensitive film material after processing.
It is still a further object of the present invention to provide a silver halide X-ray photographic material containing thin tabular silver halide grains which is improved, after having been indirectly exposed to X-rays in a film/screen combination with an intensifying luminescent screen, with respect to the dependence of sensitivity in varying processing conditions, i.e., even in a processing cycle wherein a weak developer or a nearly exhausted developer is used.
SUMMARY OF THE INVENTION
As a result of various investigations, it has been found that the above-described problems can effectively be overcome and that the objects of the present invention can be attained by providing a silver halide photographic film material having at least one emulsion comprising {111} tabular silver halide grains rich in silver bromide, spectrally sensitive to irradiation in the (green) wavelength range between 540 and 555 nm by the presence of a combination of at least one J-aggregating spectrally sensitizing cyanine dye according to the general formula (I), and of at least one additional cyanine dye, characterized in that said additional cyanine dye or dyes provide(s) a shift of maximum absorption wavelength of said combination being less than 10 nm versus in the absence thereof, wherein said at least one monomethine cyanine dye corresponds to the formula (II), and wherein it is essential that said monomethine cyanine dye has at least one solubilizing group.
In a further embodiment an azacyanine dye is additionally present.
The formulae (I) and (II) will further be explained both in the detailed description hereinafter and in the claims.
Moreover a radiographic screen/film combination has been claimed, said combination comprising a duplitized film material sandwiched between a pair of supported or self-supporting X-ray intensifying screens, characterized in that said pair of supported or self-supporting X-ray intensifying screens essentially consists of luminescent phosphor particles emitting at least 50% of their emitted radiation in the wavelength range between 540 and 555 nm, and wherein said film material is a material according to the present invention as claimed.
DETAILED DESCRIPTION OF THE INVENTION
In order to prevent loss of speed and in order to prevent residual color or dye stain after processing it is advised not to use antihalation dyes as those described e.g. in U.S. Pat. No. 5,298,378 which are favorable in order to reduce internal scatter and print-through as disclosed therein, although dye stain may also be present after processing due to the presence, in high amounts of spectra
Callant Paul
Elst Kathy
Mans Ilse
Agfa-Gevaert
Guy Josephy T.
Letscher Geraldine
Nexsen Pruet Jacobs & Pollard LLC
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