Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Identified radiation sensitive composition with color...
Reexamination Certificate
2000-06-13
2002-10-29
Baxter, Janet (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Identified radiation sensitive composition with color...
C430S583000, C430S546000, C430S607000
Reexamination Certificate
active
06472134
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to silver halide photographic materials having both improved sensitivity and reduced fogging. This invention specifically relates to photographic materials comprising amido compounds and fragmentable electron donating compounds.
BACKGROUND OF THE INVENTION
Fragmentable electron donating compounds have been disclosed which are capable of enhancing both the intrinsic sensitivity and, if a dye is present, the spectral sensitivity of silver halide emulsions. Fragmentable electron donating compounds are described more fully in U.S. Pat. Nos. 5,747,235, 5,747,236, 5,994,051, and 6,010,841, and published European Patent Applications 893,731 and 893,732. Unfortunately, the use of fragmentable electron donating compounds has been accompanied by an increase in fog growth under high temperature conditions.
Problems with fogging have plagued the photographic industry from its inception. Fog is a deposit of silver or dye that is not directly related to the image-forming exposure, i.e., when a developer acts upon an emulsion layer, some reduced silver is formed in areas that have not been exposed to light. Fog can be defined as a developed density that is not associated with the action of the image-forming exposure, and is usually expressed as “D-min”, the density obtained in the unexposed portions of the emulsion. Density, as normally measured, includes both that produced by fog and that produced as a function of exposure to light. It is known in the art that the appearance of photographic fog related to intentional or unintentional reduction of silver ion (reduction sensitization) can occur during many stages of preparation of the photographic element including silver halide emulsion preparation, spectral/chemical sensitization of the silver halide emulsion, melting and holding of the liquid silver halide emulsion melts, subsequent coating of silver halide emulsions, and prolonged natural and artificial aging of coated silver halide emulsions. The chemicals used for preventing fog growth as a result of aging or storage are generally known as emulsion stabilizers.
The control of fog, whether occurring during the formation of the light-sensitive silver halide emulsion, during the spectral/chemical sensitization of those emulsions, during the preparation of silver halide compositions prior to coating on an appropriate support, or during the aging of such coated silver halide compositions, has been attempted by a variety of means. Mercury-containing compounds, such as those described in U.S. Pat. Nos. 2,728,663; 2,728,664; and 2,728,665, have been used as additives to control fog. Thiosulfonates and thiosulfonate esters, such as those described in U.S. Pat. Nos. 2,440,206; 2,934,198; 3,047,393; and 4,960,689, have also been employed. Organic dichalcogenides, for example, the disulfide compounds described in U.S. Pat. Nos. 1,962,133; 2,465,149; 2,756,145; 2,935,404; 3,184,313; 3,318,701; 3,409,437; 3,447,925; 4,243,748; 4,463,082; and 4,788,132 have been used not only to prevent formation of fog but also as desensitizers and as agents in processing baths and as additives in diffusion transfer systems
Recently, a class of compounds has been reported to have benefits in stabilizing silver halide emulsions against such changes due to storage at high temperature and humidity. This class of sulfur heterocycle are compounds in which one of the two sulfur atoms in a five-membered heterocyclic ring is oxidized either to the tetravalent state (dithiolone dioxide) or to the trivalent state (dithiolone oxide). U.S. Pat. No. 5,693,460 teaches the stabilizing properties of dithiol-3-one 1,1-dioxides. U.S. Pat. No. 5,670,307 describes the combination of dithiol-3-one 1,1-dioxides with sulfinates. U.S. Pat. No. 5,756,278 relates to the combination of water soluble gold sensitizers with dithiolone dioxide compounds for enhanced emulsion sensitivity. U.S. Pat. No. 5,677,119 describes the stabilizing properties of dithiol-3-one 1-oxide in silver halide light sensitive materials.
U.S. Pat. No. 4,255,510 and U.S. Pat. No. 4,256,881 describe blocked benzotriazoles as development restrainers for color diffusion transfer photographic elements. UK Patent GB 2,062,884(A) discloses a photographic dye image-receiving sheet containing a blocked 5-mercaptotetrazole development restrainer. Blocked mercaptotetrazoles are also described in U.S. Pat. No. 4,442,290 and U.S. Pat. No. 4,888,268. In addition, various blocked antifoggants and development restrainers have been disclosed in Japanese Patent No. 586,882 and U.S. Pat. Nos. 3,364,028, 3,575,699 and 3,649,267.
Despite all the efforts in this field there still remains a need for compounds which act as effective antifoggants in photographic elements which are stored under high temperature conditions. Such a need particularly exists for photographic elements containing fragmentable electron donating compounds.
SUMMARY OF THE INVENTION
This invention provides a silver halide photographic element comprising at least one silver halide emulsion, said silver halide element further comprising an amido compound represented by Formula 1
wherein INH is a development inhibitor;
LINK is a linking or timing group and m is 0, 1 or 2; and
R
1
and R
2
independently represents an aliphatic, aromatic or heterocyclic group, or R
1
and R
2
together with the nitrogen to which they are attached represent the atoms necessary to form a 5 or 6 membered ring or multiple ring system; or R
1
and R
2
are independently a —C(═O)(LINK)
m
—INH group, or are substituted with an —NR
3a
C(═O)LINK)
m
—INH group, with R
3a
being defined the same as R
1
or R
2
, and wherein the compound of Formula I does not substantially react with oxidized developer to release INH; and a fragmentable electron donor compound of the formula X—Y′ or a compound which contains a moiety of the formula —X—Y′;
wherein
X is an electron donor moiety, Y′ is a leaving proton H or a leaving group Y, with the proviso that if Y′ is a proton, a base, &bgr;
−
, is covalently linked directly or indirectly to X, and wherein:
1) X—Y′ has an oxidation potential between 0 and about 1.4 V; and
2) the oxidized form of X—Y′ undergoes a bond cleavage reaction to give the radical X
•
and the leaving fragment Y′, and optionally.
3) the radical X
•
has an oxidation potential ≦−0.7V.
The photographic elements of this invention demonstrate increased sensitivity in addition to reduced fogging under high temperature conditions. The amido compounds contained in such elements provide the antifoggant effect only when needed, i.e. at high storage temperatures, thus reducing the possibility of undesirable sensitometric effects. They may also provide the antifoggant effect when the photographic element is developed under high temperature conditions. The amido compounds do not season out of the photographic elements during processing, thereby reducing seasoning of the photographic processing solutions. Unintentional seasoning of such solutions with antifogging or stabilizing compounds can also cause undesirable sensitometric effects.
DETAILED DESCRIPTION OF THE INVENTION
The amido compounds of this invention are blocked antifoggants represented by the following Formula 1.
The compounds of Formula 1 are not couplers and do not substantially react with oxidized color developing agent to form dye and release INH during normal processing conditions. That is, when the amido compounds are processed in developer as described below, the INH moiety is not released. A suitable test involves placing an amido compound in the following developer solution; para-phenylenediamine (4.5 g/l), potassium carbonate (34.4 g/l), potassium bicarbonate (2.3 g/l) at pH 10 to which has also been added 1 g/l of potassium ferricyanide to oxidize the developer to Dox. Under these conditions at 40 deg C, inhibitor-releasing couplers that are well known in the art will react substantially in three minutes to form dye and release their inhibitors. However, th
Burgmaier George J.
Muenter Annabel A.
Reynolds James H.
Szatynski Steven P.
Baxter Janet
Eastman Kodak Company
Meeks Roberts Sarah
Walke Amanda C.
LandOfFree
Silver halide element with improved high temperature storage... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Silver halide element with improved high temperature storage..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Silver halide element with improved high temperature storage... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2992589