Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2002-11-19
2004-04-27
Letscher, Geraldine (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S599000, C430S604000, C430S605000
Reexamination Certificate
active
06727055
ABSTRACT:
FIELD OF THE INVENTION
This invention is directed to radiation sensitive high bromide silver halide cubic grain photographic emulsions. It particularly relates to high bromide silver iodochlorobromide cubic grain emulsions doped with a metal ion coordination complex.
DEFINITION OF TERMS
In referring to grains and emulsions containing two or more halides, the halides are named in order of ascending concentrations.
The term “high bromide” in referring to silver halide grains and emulsions indicate greater than 50 mole percent bromide, based on total silver.
The term “equivalent circular diameter” or “ECD” indicates the diameter of a circle having an area equal to the projected area of a grain or particle.
The term “size” in referring to grains and particles, unless otherwise described, indicates ECD.
The term “regular grain” refers to a silver halide grain that is internally free of stacking faults, which include twin planes and screw dislocations.
The term “cubic grain” is employed to indicate a regular grain that is bounded by six {100} crystal faces. Typically the corners and edges of the grains show some rounding due to ripening, but no identifiable crystal faces other than the six {100} crystal faces. The six {100} crystal faces form three pairs of parallel {100} crystal faces that are equidistantly spaced.
The term “cubical grain” is employed to indicate grains that are at least in part bounded by {100} crystal faces satisfying the relative orientation and spacing of cubic grains. That is, three pairs of parallel {100} crystal faces are equidistantly spaced. Cubical grains include both cubic grains and grains that have one or more additional identifiable crystal faces. For example, tetradecahedral grains having six {100} and eight {111} crystal faces are a common form of cubical grains.
The term “roundness coefficient” (hereinafter assigned the symbol “n”) and the term “roundness index” (hereinafter assigned the symbol “Q”) are measures of the degree to which silver halide grain comers are rounded as defined by Mehta et al. in U.S. Pat. No. 6,048,683. “n” is chosen to satisfy the formula x
n
+y
n
=R
n
, where R is any vector extending from the center of a {100} crystal face of a grain to the projected peripheral edge of the grain viewed normal to the {100} crystal face, x is an X axis coordinate of R, y is a Y axis coordinate of R, and X and Y are mutually perpendicular axes in the plane of the {100} crystal face. For a circle, the roundness coefficient is 2, while for a square the roundness coefficient is increased to infinity. For convenience, roundness index Q is defined as being equal to 2
. Thus, the Q of a square is zero, while that for a circle is 1. The degree to which regular silver halide grains having {100} crystal faces exhibit comer rounding is determined by looking at the projected area of a grain in a photomicrograph viewed normal to a {100} crystal face. The value of n that most closely matches the peripheral boundary of the {100} grain face is the roundness coefficient of the grain. From measurement of a representative number of grains, an average roundness coefficient n and roundness index Q can be determined for an emulsion.
The term “central portion” or “core” in referring to silver halide grains refers to an interior portion of the grain structure that is first precipitated relative to a later precipitated portion.
The term “shell” in referring to silver halide grains refers to an exterior portion of the silver halide grain which is precipitated on a central portion.
The term “dopant” is employed to indicate any material within the rock salt face centered cubic crystal lattice structure of a silver halide grain other than silver ion or halide ion.
The term “dopant band” is employed to indicate the portion of the grain formed during the time that dopant was introduced to the grain during precipitation process.
The term “log E” is the logarithm of exposure in lux-seconds. Photographic speed is reported in relative log units and therefore referred to as relative log speed. 1.0 relative log speed unit is equal to 0.01 log E.
The term “contrast” or “&ggr;” is employed to indicate the slope of a line drawn from stated density points on the characteristic curve.
The term “rapid access processing” and “rapid access processor” are employed to indicate the capability of providing dry-to-dry processing in 90 seconds or less. The term “dry-to-dry” is used to indicate the processing cycle that occurs between the time a dry, imagewise exposed element enters a processor to the time it emerges, developed, fixed and dry
The term “reciprocity law failure” refers to the variation in response of an emulsion to a fixed light exposure due to variation in the specific exposure time.
Research Disclosure
is published by Kenneth Mason Publications, Ltd., Dudley House, 12 North St., Emsworth, Hampshire P010 7DQ, England.
All references to the periodic table of elements periods and groups 2 0 in discussing elements are based on the Periodic Table of Elements as adopted by the American Chemical Society and published in the
Chemical and Engineering News
, Feb. 4, 1985, p. 26. The term “Group VIII” is used to generically describe elements in groups 8, 9 and 10.
BACKGROUND OF THE INVENTION
Radiation sensitive silver halide emulsions are used in conventional photograph elements and other imaging systems to record imagewise exposures, where the silver halide emulsions employed are selected or designed to provide desired performance attributes. The use of dopants in silver halide grains to modify photographic performance is well know in the photographic art, as generally illustrated, e.g., by
Research Disclosure
, Item 38957, I. Emulsion grains and their preparation, D. Grain modifying conditions and adjustments, paragraphs (3)-(5). Photographic performance attributes known to be affected by dopants include sensitivity, reciprocity failure, and contrast.
The contrast of photographic elements containing silver halide emulsions can generally be increased by incorporating into the silver halide grains a dopant capable of creating deep electron trapping sites, such as illustrated by R. S. Eachus, R. E. Graves and M. T. Olm
J Chem. Phys
., Vol. 69, pp. 4580-7 (1978) and
Physica Status Solidi A
, Vol. 57, 429-37 (1980) and R. S. Eachus and M. T.
Olm Annu. Rep. Prog. Chem. Sect. C. Phys. Chem
., Vol. 83, 3, pp. 3-48 (1986). While deep electron trapping dopants are effective at increasing contrast of photographic elements, significant speed losses in such elements are also generally associated with their use.
Using empirical techniques the art has over the years identified many dopants capable of increasing photographic speed. Keevert et al U.S. Pat. No. 4,945,035, e.g., was the first to teach the incorporation of a hexacoordination complex containing a transition metal and cyano ligands as a dopant in high chloride grains to provide increased sensitivity. Marchetti et al. U. S. Pat. No. 4,937,180 teaches the incorporation of hexacoordination complex containing rhenium, ruthenium, osmium, or iridium and cyano ligands in high bromide grains optionally containing iodide. Scientific investigations have gradually established that one general class of speed increasing dopants share the capability of providing shallow electron trapping sites. Olm et al U.S. Pat. No. 5,503,970 and Daubendiek et al U.S. Pat. Nos. 5,494,789 and 5,503,971, here incorporated by reference, as well as
Research Disclosure
, Vol. 367, November 1994, Item 36736, were the first to set out comprehensive criteria for a dopant to have the capability of providing shallow electron trapping sites.
Doping with iridium is commonly performed to reduce reciprocity law failure in silver halide emulsions. According to the photographic law of reciprocity, a photographic element should produce the same image with the same exposure, even though exposure intensity and time are varied.
Adin Anthony
Beal Richard E.
Gingello Anthony D.
Hershey Stephen A.
Mee John D.
Anderson Andrew J.
Eastman Kodak Company
Letscher Geraldine
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