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US 5,449,595 AGranted
Method for making direct-positive photographic images
AssigneeAgfa-Gevaert
InventorsJean-Marie Dewanckele, David Terrell, Kris Viaene
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AssigneeAgfa-Gevaert
InventorsJean-Marie Dewanckele, David Terrell, Kris Viaene
Estimating the term…
The present invention relates to a method for making direct-positive photographic images by developing light-sensitive materials in the presence of development nucleators which do not cause loss of sensitivity during exposure or unevenness of development. More specifically the invention relates to the formation of direct-positive images having a high maximum density and high exposure latitude and to photographic materials for use in said formation, which is accomplished by a method for making direct-positive images comprising: image-wise exposing a photographic light-sensitive silver halide material comprising a support and a layer of an internal latent image-type silver halide emulsion, the pAg of which has been adjusted to a pAg-value between 9.0 and 10.5 inclusive before coating, and developing said exposed photographic silver halide material in a surface developer in the presence of a development nucleator with a group promoting adsorption to silver halide. It has been found that in a particular embodiment of this invention a development-nucleating amount of a hydrazine compound with a 7-hydroxy-s-triazolo-[1,5-a]-pyrimidine group as group promoting adsorption to silver halide is very useful.
Photographic light-sensitive silver halide material, said material comprising a support and in at least one light-sensitive emulsion layer comprising internal latent image-type silver halide grains dispersed in a hydrophilic binder and/or in a hydrophilic colloid layer in water-permeable relationship with the said emulsion layer, at least one development nucleating agent which is a hydrazine compound with a 7-hydroxy-s-triazolo-[1,5-a]-pyrimidine group the pAg of said emulsion having been adjusted to a pAg of between 9.0 and 10.5 inclusive before coating.
Dependencies are inferred from the claim text.