Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Two or more radiation-sensitive layers containing other than...
Reexamination Certificate
2000-10-17
2002-02-26
Schilling, Richard L. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Two or more radiation-sensitive layers containing other than...
C430S505000, C430S506000, C430S509000, C430S566000, C430S600000, C430S614000, C430S615000
Reexamination Certificate
active
06350564
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
Co-filed herewith is an application (pending U.S. Ser. No. 09/690,569) directed to a light sensitive color photographic element containing a speed improving nitrogen heterocycle with at least 3 heteroatoms and a certain class of Electron Transfer Agent Releasing Compounds (ETARCs) and an application (pending U.S. Ser. No. 09/690,230) directed to an element containing a certain reflector layer.
FIELD OF THE INVENTION
This invention relates to a light sensitive color photographic clement containing a speed improving nitrogen heterocycle with at least 3 heteroatoms and a non-light sensitive light reflecting silver halide material.
DEFINITION OF TERMS
The term “equivalent circular diameter” or “ECD” is employed to indicate the diameter of a circle having the same projected area as a silver halide grain.
The term “aspect ratio” designates the ratio of grain ECD to grain thickness (t).
The term “tabular grain” indicates a grain having two parallel crystal faces that are clearly larger than any remaining crystal face and having an aspect ratio of at least 5.
The term “3-D” indicates a grain that is not a tabular grain as defined above.
The term “tabular grain emulsion” refers to an emulsion in which tabular grains account for greater than 50 percent of total grain projected area.
The term “non-tabular grain emulsion” refers to an emulsion in which tabular grains account for 50 percent or less of the total grain projected area.
The term “small 3-D grain emulsion” refers to a tabular or non-tabular grain emulsion in which at least 20 mol % of the grains in the emulsion are 3-D grains having an ECD in the range of 0.1 to 0.8 &mgr;m.
The term “high bromide” in referring to grains and emulsions indicates that bromide is present in a concentration greater than 50 mole percent,
In referring to silver halide grains and emulsions containing two or more halides, the halides are named in order of ascending concentrations, based on total silver.
The terms “blue”, “green” and “red” indicate the portions of the visible spectrum lying, respectively, within the wavelength ranges of from 400 to 500 nm, 500 to 600 nm and 600 to 700 nm.
The term “minus blue” indicates the visible portion of the spectrum outside the blue portion of the spectrum—e.g., any spectral region in the range of from 500 to 700 nm.
The term “half peak absorption bandwidth” indicates the spectral region over which a dye exhibits an absorption equal to half its peak absorption.
The terms “front” and “back” indicate a position that is nearer or farther, respectively, than the support from the source of exposing radiation, with the support being on the back.
The terms “above” and “below” indicate a position nearer or farther, respectively, from the source of exposing radiation, with the support being on the bottom.
The term “stop” in comparing photographic speeds indicates an exposure difference of 0.3 log E required to produce the same reference density, where E is exposure in lux-seconds.
The term relatively non-light sensitive when referring to the grains of an emulsion means that the emulsion exhibits no more than 10% of the sensitivity of any of the red-light sensitive layers, as measured by red toe speed.
The term “maximum gamma” is herein defined as the highest observed ratio of &Dgr;D/&Dgr;E, where &Dgr;D is the increase in density that occurs in response to an increase in exposure &Dgr;E.
BACKGROUND OF THE INVENTION
It is a long-standing objective of color photographic origination materials to maximize the overall response to light while maintaining the lowest possible granularity. Increased photographic sensitivity to light (commonly referred to as photographic speed) allows for improved images captured under low light conditions or improved details in the shadowed regions of the image. Sensitivity is much more important with origination materials than with print materials, the latter depending entirely on operator supplied light. In general, the overall light sensitivity provided by the light sensitive silver halide emulsions is a function of the size of the emulsion grains. Larger emulsion grains capture more light. Upon development, the captured light is ultimately converted into dye deposits that constitute the reproduced image. Undesirably, the granularity exhibited by these dye deposits is directly proportional to the grain size of the silver halide emulsion. Thus, larger silver halide emulsion grains have higher sensitivity to light but also lead to higher granularity in the reproduced image. Therefore, it is a fundamental problem in photography to improve the light sensitivity of a silver halide element without a corresponding decrease in another property such as granularity. In this description, it will be understood that the demonstrated increase in sensitivity is accomplished without a significant sacrifice in granularity. Stated from another perspective, it has been a long-standing problem to provide materials which maximize the response to light of a silver halide emulsion for any given grain size. It is highly desirable to provide non-imaging materials that lead to increased photographic speed without having to increase the size of the light-sensitive silver halide grains.
European Publication EP 1 016 902 describes the use of certain compounds, including heterocycles with a ClogP of 6.2 or greater, in a light sensitive silver halide emulsion layer, or in an adjacent non-light sensitive layer to increase the overall light sensitivity of a photographic element.
U.S. Pat. No. 3,989,527 discloses a method of increasing photographic speed whereby a light insensitive reflecting emulsion having a particle size from 0.40 -0.60 &mgr;m is blended within a sensitized emulsion. U.S. Pat. No. 5,994,042, U.S. Pat. No. 5,994,043, U.S. Pat. No. 5,998,113, U.S. Pat. No. 5,998,114, U.S. Pat. No. 6,001,548 and U.S. Pat. No. 5,998,115 all describe the use of non-light sensitive light scattering or reflecting emulsions, or a combination thereof, to increase photographic speed.
Electron Transfer Agent Releasing Compounds (ETARCs) are taught in U.S. Pat. No. 4,859,578 and U.S. Pat. No. 4,912,025 and their use with Soluble Mercaptan Releasing Couplers (SMRCs) is taught in European Publication EP 1 016 912. ETARCs can improve the developability of silver halide emulsions which in some cases, offers improvements in light sensitivity.
Thus it is known to incorporate various materials such as those that cause light reflecting, and certain heterocyclic compounds or ETARCs to improve the light sensitivity of photographic elements. A problem to be solved is to provide color photographic elements that exhibit still further improved photographic speed.
SUMMARY OF THE INVENTION
The invention provides a color silver halide photographic element comprising a support bearing:
(1) a light sensitive silver halide emulsion layer;
(2) a nitrogen heterocycle with a minimum of three heteroatoms that does not react with oxidized developer, does not contain free thiol substituents, and has a ClogP sufficient to increase the photographic speed of said element compared to the same element without the compound, said heterocycle compound located either in said light sensitive layer or in a layer adjacent to it; and
(3) a light reflecting silver halide material;
provided that the heterocycle compound and the light reflecting material are located either (a) in different layers of the element located close enough to each other so that a super-additive speed increase is realized or (b) in the same light sensitive layer.
The invention provides color photographic elements that exhibit a desirable increase in photographic speed.
DETAILED DESCRIPTION OF THE INVENTION
The invention is generally as described above. Typically, the color photographic element useful in the present invention contains at least one red sensitive silver halide emulsion layer with at least one non-diffusing cyan coupler, at least one green sensitive silver halide emulsion layer with at least one non-diffusing magenta coupler and at least one blue sensi
Bringley Joseph F.
Friday James A.
Singer Stephen P.
Vitale Marcello
Eastman Kodak Company
Kluegel Arthur E.
Schilling Richard L.
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