Radiation imagery chemistry: process – composition – or product th – Silver halide colloid tanning process – composition – or product
Reexamination Certificate
2001-06-26
2002-08-13
Schilling, Richard L. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Silver halide colloid tanning process, composition, or product
C430S517000, C430S529000, C430S508000, C430S533000, C430S534000, C430S535000
Reexamination Certificate
active
06432606
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an improved photographic recording material for graphic arts prepress.
BACKGROUND OF THE INVENTION
Photosensitive materials based on silver halide chemistry are used in a lot of applications, e.g. photographic materials for general amateur and professional photography in black-and white or color, recording and printing materials for the motion picture industry, and materials for the recording and duplication of medical diagnostic images. Further specific materials are developed for micrography, non-destructive testing and graphic arts pre-press. In graphic arts reproduction processes the original image appearing to have a continuous tone gradation is reproduced in a screening process by a collection of large number of dots, either by optical means in the case of a camera film or by electronic means in case of a recorder film. Apart from camera and recorder films there exist also so-called contact films which are able to duplicate screened images. In several photographic areas but in particular in graphic arts prepress films there is permanent need for lower manufacturing costs, higher covering power, sharper images, and reduced replenishment rates. This is especially the case for films with a great turnover such as a graphic arts recorder film which is designed for the recording of screened images, linework and text electronically stored in an image-setter or scanner.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide a graphic arts recording film with improved covering power.
It is a further object of the present invention to provide a graphic arts recording film with lowered manufacturing costs.
SUMMARY OF THE INVENTION
The above mentioned objects are realized by providing a photographic recording material for graphic arts comprising a polyester support, subbed on both front and back sides with a latex subbing layer, and further comprising on the front side a gelatin subbing layer, one or more red sensitized emulsion layers having a total silver coverage of at most 3.6 g/m
2
Ag (corresponding to 5.5 g/m
2
, expressed as AgNO
3
), and a total dry coverage of all other solid ingredients of at most 1.5 g/m
2
, and one or more anti-abrasive layers.
In a preferred embodiment the photographic recording material further comprises on the back side an antihalation layer comprising at most 1.5 g/m
2
of gelatin and an antihalation dye.
DETAILED DESCRIPTION OF THE INVENTION
The different elements of the invention will now be explained in detail.
The Emulsion Layer
The recording material of the present invention contains one or more emulsion layers, containing silver halide grains, a binder and other solid ingredients. In a most preferred embodiment of this invention there is just one emulsion layer. It is an essential feature of the present invention that the total silver coverage is at most 3.6 g/m
2
Ag (corresponding to 5.5 g/m
2
expressed as AgNO
3
). It is a further essential feature of the present invention that the total dry coverage of all other solid ingredients is at most 1.5 g/m
2
.
Graphic arts recording materials preferably use emulsions containing a majority of chloride, preferably between 50 mole % and 95 mole %, most preferably between 60 mole % and 89 mole %, and a low amount of iodide, the remaining halide being bromide.
The photographic emulsion(s) can be prepared from soluble silver salts and soluble halides according to different methods as described e.g. by P. Glafkidès in “Chimie et Physique Photographique”, Paul Montel, Paris (1967), by G. F. Duffin in “Photographic Emulsion Chemistry”, The Focal Press, London (1966), and by V. L. Zelikman et al in “Making and Coating Photographic Emulsion”, The Focal Press, London (1966). They can be prepared by mixing the halide and silver solutions in partially or fully controlled conditions of temperature, concentrations, sequence of addition, and rates of addition. The silver halide can be precipitated according to the single-jet method, the double-jet method, the conversion method or an alternation of these different methods.
The silver halide emulsions can be doped with various metal salts or complexes such as Rhodium and Iridium dopants.
The emulsion can be desalted in the usual ways e.g. by dialysis, by flocculation and re-dispersing, or by ultrafiltration.
The light-sensitive silver halide emulsions are preferably chemically sensitized as described e.g. in the above-mentioned “Chimie et Physique Photographique” by P. Glafkidès, in the above-mentioned “Photographic Emulsion Chemistry” by G. F. Duffin, in the above-mentioned “Making and Coating Photographic Emulsion” by V. L. Zelikman et al, and in “Die Grundlagen der Photographischen Prozesse mit Silberhalogeniden” edited by H. Frieser and published by Akademische Verlagsgesellschaft (1968). As described in said literature chemical sensitization can be carried out by effecting the ripening in the presence of small amounts of compounds containing sulphur e.g. thiosulphate, thiocyanate, thioureas, sulphites, mercapto compounds, and rhodamines. The emulsions can be sensitized also by means of gold-sulphur ripeners, gold-selenium ripeners or by means of reductors e.g. tin compounds as described in GB 739,823, amines, hydrazine derivatives, formamidine-sulphinic acids, and silane compounds. Chemical sensitization can also be performed with small amounts of Ir, Rh, Ru, Pb, Cd, Hg, Tl, Pd, Pt, or Au. One of these chemical sensitization methods or a combination thereof can be used.
The light-sensitive silver halide emulsions can be red sensitized with proper dyes such as those described by F. M. Hamer in “The Cyanine Dyes and Related Compounds”, 1964, John Wiley & Sons. Dyes that can be used for the purpose of spectral sensitization include cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, hemicyanine dyes, styryl dyes and hemioxonol dyes. Particularly valuable dyes are those belonging to the cyanine dyes, merocyanine dyes and complex merocyanine dyes. Specific patents on red sensitizers include U.S. Pat. No. 4,717,650, FR 2 058 405 and EP 427892.
The silver halide emulsion(s) for use in accordance with the present invention may comprise compounds preventing the formation of fog or stabilizing the photographic characteristics during the production or storage of photographic elements or during the photographic treatment thereof. Many known compounds can be added as fog-inhibiting agent or stabilizer to the silver halide emulsion. Suitable examples are disclosed in
Research Disclosure
Item 36544, September 1994, Chapter VII.
Besides the silver halide another essential component of a light-sensitive emulsion layer is the binder. The binder is a hydrophilic colloid, preferably gelatin. Gelatin can, however, be replaced in part or integrally by synthetic, semi-synthetic, or natural polymers.
The binders of the photographic element, especially when the binder used is gelatin, can be hardened with appropriate hardening agents such as those of the epoxide type, those of the ethylenimine type, those of the vinylsulfone type e.g. 1,3-vinylsulpohonyl-2-propanol, chromium salts e.g. chromium acetate and chromium alum, aldehydes e.g. formaldehyde, glyoxal, and glutaraldehyde, N-methylol compounds e.g. dimethylolurea and methyloldimethylhydantoin, dioxan derivatives e.g. 2,3-dihydroxy-dioxan, active vinyl compounds e.g. 1,3,5-triacryloyl-hexahydro-s-triazine, active halogen compounds e.g. 2,4-dichloro-6-hydroxy-striazine, and mucohalogenic acids e.g. mucochloric acid and mucophenoxychloric acid. These hardeners can be used alone or in combination. The binders can also be hardened with fast-reacting. hardeners such as carbamoylpyridinium salts as disclosed in U.S. Pat. No. 4,063,952.
In a preferred embodiment of the present invention the emulsion layer further contains a polymeric latex functioning as plasticizer. A preferred latex is copoly(AMPS-butylmethacrylate), wherein AMPS means 2-acrylamido-2-methylpropane sulphonic acid, sodium salt, a monomer from Lubrizol Co. In a mos
Claes Roland
Lingier Stefaan
Thillo Etienne Van
Agfa-Gevaert
Guy Joseph T.
Nexsen Pruet Jacobs & Pollard LLC
Schilling Richard L.
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