Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Identified radiation sensitive composition with color...
Reexamination Certificate
1999-12-20
2001-05-29
Letscher, Geraldine (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Identified radiation sensitive composition with color...
C430S558000, C430S505000, C430S955000, C430S957000
Reexamination Certificate
active
06238855
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to photographic elements, such as colour negative films, and in particular to those which contain one or more aromatic bicyclic heterocycles containing an imidazole or pyrazole nucleus which can be used as coupling-off groups to give DIR couplers.
BACKGROUND OF THE INVENTION
Many silver halide photographic elements, in particular color negative films, contain so-called DIR (development inhibitor releasing) couplers. DIR couplers release inhibitors that can restrain silver development in the layer in which release occurs, as well as in other layers of a multilayer photographic material. DIR couplers can help control gamma (contrast), enhance sharpness (acutance), reduce granularity and provide color correction via interlayer interimage effects. U.S. Pat. No. 3,933,500 broadly discloses DIR couplers with azole-type coupling off groups. EP-A-0 867 763 A describes purines and 1H-pyrazolo[3,4-d]pyrimidines as DIR couplers. A specific class of DIR couplers is DI(A)R couplers (development inhibitor anchiomeric-releasing) in which the release of the inhibitor is controlled by a timing mechanism.
It is desirable that DIR couplers efficiently reduce photographic contrast to provide benefits such as enhanced sharpness, reduced granularity and improved exposure latitude. It is also desirable that they give a reduction in the total amount of developed dye density (D
max
).
U.S. Pat. No. 5,356,764 discloses the use of silver chloride emulsions in combination with DIRS incorporated at typically low levels with an image dye-forming coupler, e.g. the DIR comprises less than 8% of the total amount of coupler. EP 0 867 763A describes DIRs in an element containing silver chloride or silver bromoiodide at less than 11% of the total amount of coupler. JP-4278942 exemplifies silver iodide and silver bromoiodide-containing elements including DIRS at low percentage of total coupler, providing materials with good sharpness and superior shelf stability.
Silver chloride emulsions typically enable faster and easier processing, including faster and easier development, bleaching and fixing, combined with lower environmental impact.
PROBLEM TO BE SOLVED BY THE INVENTION
A problem, however, with such silver chloride emulsions is that proper development inhibition is much more difficult to achieve than with silver bromoiodide emulsions because of their superior developability. Thus there has been a need for a method of effectively reducing contrast and maximum amount of dye formed in elements containing silver chloride emulsions.
It has now been found that such inhibition of silver chloride emulsions can be achieved by incorporating the DI(A)R coupler at considerably higher than typical molar percentage of total amount of coupler.
SUMMARY OF THE INVENTION
According to the present invention there is provided a photographic element comprising a support bearing one or more silver halide emulsions, at least one of which comprises at least 50% silver chloride, in association with one or more image dye-forming couplers and one or more DI(A)R couplers of formulae I or II:
wherein:
Z is a moiety which can react with oxidized developer to release a coupling-off group;
R
1
is a hydrogen atom or a group selected from a halogen atom and an unsubstituted or substituted alkyl, aryl, alkoxy, aryloxy, alkyl- or aryl-thio, amino, alkyl- or aryl-amino, carbonamido, carbamoyl, alkoxy- or aryloxy-carbonyl, alkyl- or aryl-carbonyl, sulfonyl and sulfonamido group;
each of the R
2
substituents is a halogen atom or a group selected from an unsubstituted or substituted alkyl, aryl, alkoxy, aryloxy, alkyl- or aryl-thio, amino, alkyl- or aryl-amino, carbonamido, carbamoyl, alkoxy- or aryloxy-carbonyl, alkyl- or aryl-carbonyl, sulfonyl and sulfonamido group;
X represents the atoms required to make a second ring which is aromatic and contains at least one nitrogen atom;
n is from 0 to the number of carbon atoms in the second ring, with the proviso that if R
1
is hydrogen, n is at least 1;
TIME is a timing group and
j is 0,1 or 2,
wherein the DI(A)R coupler(s) in association with an emulsion comprising at least 50% silver chloride comprise at least about 25% to about 90% of the total amount of coupler in association with that emulsion and the total amount of coupler is the sum of the number of moles of image coupler(s) and the number of moles of the DI(A)R coupler(s) in association with that emulsion.
In another aspect of the invention there is provided a multicolour photographic element comprising a support bearing a cyan image-dye-forming unit comprising a red-sensitive silver halide emulsion layer and a cyan dye-forming coupler; a magenta image-dye-forming unit comprising at least one green-sensitive silver halide emulsion layer and a magenta dye-forming coupler; a yellow image-dye-forming unit comprising at least one blue-sensitive silver halide layer and a yellow dye-forming coupler, and associated therewith one or more DI(A)R couplers of formulae (I) or (II)
wherein:
Z is a moiety which can react with oxidized developer to release a coupling-off group;
R
1
is a hydrogen atom or a group selected from a halogen atom and an unsubstituted or substituted alkyl, aryl, alkoxy, aryloxy, alkyl- or aryl-thio, amino, alkyl- or aryl-amino, carbonamido, carbamoyl, alkoxy- or aryloxy-carbonyl, alkyl- or aryl-carbonyl, sulfonyl and sulfonamido group;
each of the R
2
substituents is a halogen atom or a group selected from an unsubstituted or substituted alkyl, aryl, alkoxy, aryloxy, alkyl- or aryl-thio, amino, alkyl- or aryl-amino, carbonamido, carbamoyl, alkoxy- or aryloxy-carbonyl, alkyl- or aryl-carbonyl, sulfonyl and sulfonamido group;
X represents the atoms required to make a second ring which is aromatic and contains at least one nitrogen atom;
n is from 0 to the number of carbon atoms in the second ring, with the proviso that if R
1
is hydrogen, n is at least 1;
TIME is a timing group and
j is 0,1 or 2,
wherein at least one of the layers comprises an emulsion comprising at least 50% silver chloride in association with one or more of the DI(A)R couplers, said DI(A)R couplers comprising at least about 25% to about 90% of the total amount of coupler in association with that layer, wherein the total amount of coupler is the sum of the number of moles of image coupler(s) and the number of moles of the DI(A)R couplers in association with that layer.
ADVANTAGEOUS EFFECT OF THE INVENTION
The DI(A)R couplers, when incorporated in elements of the invention, efficiently reduce development of silver chloride emulsions i.e. there is a reduction in both contrast and maximum amount of dye formed.
REFERENCES:
patent: 3933500 (1976-01-01), Shiba et al.
patent: 5356764 (1994-10-01), Szajewski et al.
patent: 5958662 (1999-09-01), Merkel et al.
patent: 5989798 (1999-11-01), Merkel et al.
patent: 6043016 (2000-03-01), Merkel et al.
patent: 867 763 (1998-09-01), None
patent: 4278942 (1992-10-01), None
Allway Philip A.
Stanley Paul L.
Watts Christina M.
Eastman Kodak Company
Letscher Geraldine
Meeks Roberts Sarah
Walke Amanda C.
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