Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Two or more radiation-sensitive layers containing other than...
Reexamination Certificate
2001-05-21
2003-01-28
Letscher, Geraldine (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Two or more radiation-sensitive layers containing other than...
C430S567000, C430S543000, C430S553000, C430S955000, C430S505000
Reexamination Certificate
active
06511796
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a multilayer silver halide color photographic element comprising a support having coated thereon at least two red-sensitive silver halide emulsion layers having different sensitivity to red light, characterized in that the most sensitive of the red-sensitive silver halide emulsion layers comprises a core-shell silver bromoiodide tabular emulsion having a pure bromide core, a total silver iodide content lower than 10% and an aspect ratio higher than 4.0 and a SE (Speed Enhancing) cyan coupler to improve sensitometric properties.
2. Background of the Art
There have been more strict requirements in sensitometric quality for silver halide emulsions for photographic use, which has increased demand for high level photographic characteristics such as, for example, high speed, excellent graininess, high sharpness, low fog, wider exposure latitude range and on the like.
The above mentioned requirements have been satisfied by well-known silver bromoiodide grain emulsions having a high silver iodide content in the inner part of the grains and a specific core-shell structure in the grains thereof. It is well known in the photographic art that light absorbing increases in the order of silver chloride, silver bromide and silver iodide, but development activity correspondingly decreases in the same order. By using the above described core-shell silver bromoiodide emulsions, a good balance between light sensitivity and development activity has been obtained.
Examples of core-shell silver bromoiodide emulsion are described in many patent and literature references. For example, US 4,668,614 and U.S. Pat. No. 4,728,602 describe a monodispersed core-shell silver bromoiodide emulsion having a core part comprising a silver iodide content of 10 to 45 mol % and a shell part comprising a silver iodide content lower than 5 mol %, with an average silver iodide content higher than 7 mol %. When examined by X-ray diffractometry, two peaks are evident. The first peak corresponds to the high iodide core part, and the second peak corresponds to the low iodide shell part. According to the claimed invention it is preferred to have a ratio between the diffraction intensity of the two peaks in the range of from 1/10 to 3/1, and more preferably 1/3 to 3/1.
Similarly, European Application EP 299,719 discloses a core-shell silver halide emulsion having a core comprising not less than 10 mol % of silver iodide, at least one shell consisting of silver bromide or silver bromoiodide, the outermost of which has a silver iodide content not higher than 5 mol %, and an average silver iodide content of not less than 10 mol %.
EP 309,119 discloses a core-shell silver halide emulsion having at least three silver bromide or silver bromoiodide phases of different composition. According to a preferred embodiment of the claimed emulsion, the innermost phase has a silver iodide content of at least 10 mol %, the outermost phase has a silver iodide content of not more than 6 mol %, and the intermediate phase has a silver iodide content difference with the outermost or innermost phase of at least 3 mol %. When examined by X-ray diffraction, the claimed emulsion shows three or more diffraction peaks, each corresponding to a phase containing a different percentage of iodide.
EP 202,784 describes a core-shell type silver halide emulsion having an inner core essentially consisting of silver bromide or silver bromoiodide and a plurality of shells. The outermost shell has a silver iodide content ranging from 0 to 10 mol %, the innermost shell has a silver iodide content at least 6 mol % higher than that of the outermost shell, and an intermediate shell has a silver iodide content is at least 3 mol % lower than that of the innermost shell and at least 3 mol % higher than that of the outermost shell.
U.S. Pat. No. 4,477,564 describes a multiphase bromoiodide emulsion having an average silver iodide content higher than 12%.
U.S. Pat. No. 4,614,711 describes silver bromoiodide grains with a core shell structure with a core of silver bromide or bromiodide and a first layer composed of silver bromoiodide, exterior to said core and containing more iodide than said core by 10 mol % or more.
U.S. Pat. No. 5,780,216 discloses a color negative silver halide photographic material with a core shell emulsion having a plurality of shells comprising an inner core consisting essentialy of silver bromide or bromoiodide and a plurality of shells of silver bromide or silver bromoiodide comprising a high iodide shell interposed between two shells consisting essentially of silver bromide.
EP 1,055,964 discloses a light-sensitive emulsion comprising silver bromoiodide grains of a core shell structure comprising an inner core consisting essentially of silver bromide or silver bromoiodide and a plurality of shells consisting essentially of silver bromide or silver bromoiodide. In this patent application, there is no mention about the presence of Speed Enhancing (SE) cyan couplers in the most red-sensitive emulsion layer.
Couplers having a general formula similar to that of the SE cyan coouplers of the present invention have been described, for example, in U.S. Pat. No. 4,865,959, in EP Pat. Appl. Nos. 89,843, 117,511, 118,087, 193,389, and 301,477.
European Patent No. 193,389 discloses the use of compounds capable of releasing solubilized aliphatic and aromatic mercaptans as bleach accelerator releasing compounds. The use of said compounds in triple-coat structures is not specifically described therein.
U.S. Pat. No. 5,500,330 describes a photographic element comprising at least three light sensitive silver halide layers spectrally sensitized to the same region of the electromagnetic spectrum, wherein the least sensitive such layer, or a nonsensitive layer adjacent thereto, comprises a compound which contains a releasable thiol fragment or a precursor thereof.
European Patent No. 456,181 describes the use of bleach accelerator releasing couplers in multilayered color films employing triple-coated records. This usage is said to provide improved bleaching. The examples specifically disclosed in this publication illustrate the localization of the bleach accelerator releasing couplers in the most light sensitive layers of the triple-coated records or the indiscriminate addition of them into many layers of the film. Compounds capable of releasing solubilized aliphatic or solubilized aromatic mercaptans as a bleach accelerator are described.
European Patent No. 310,125 describes a silver halide color photographic material comprising at least one silver halide emulsion containing silver iodide. The average iodide content of the emulsion is at least 7 mol % and comprises at least one compound capable of releasing a bleach accelerating agent upon a reaction with an oxidation product of an aromatic primary amine type color developing agent. This compound can be added either in the low sensitive or in the most sensitive red-sensitve emulsion layer. This silver halide emulsion containing silver iodide is preferably a core-shell emulsion having a concentration of silver iodide in the core portion that is higher than that in the shell portion. The silver halide color photographic material has excellent desilvering property and good graininess.
Japanese Kokai 02/113,242 also discloses the use of bleach accelerating releasing couplers in triple-coated red or green light sensitive color records and specifically recommends localizing the bleach accelerating releasing couplers in the most light sensitive layers of a red or green color record so as to provide improved bleaching characteristics. Compounds capable of releasing solubilized aliphatic or solubilized aromatic mercaptans as bleach accelerator are described.
U.S. Pat. No. 4,865,959 discloses triple-coated red light sensitive color records. It teaches that bleaching and color reproduction can be improved by selecting a specific and narrow sub-class of cyan dye-forming image couplers and by simultaneously incorporating bleach accelerating r
Fava Simona
Poggi Antonio
Rocca Giuseppe
Ferrania S.p.A.
Letscher Geraldine
Mark A. Litman & Assoc. P.A.
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