Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2001-07-31
2003-05-13
Baxter, Janet (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S569000, C430S603000, C430S604000, C430S605000
Reexamination Certificate
active
06562559
ABSTRACT:
FIELD OF THE INVENTION
This invention is directed to radiation sensitive silver halide emulsions useful in photography, including electronic printing methods wherein information is recorded in a pixel-by-pixel mode in a radiation silver halide emulsion layer, comprising a combination of specified dopants.
DEFINITION OF TERMS
The term “high chloride” in referring to silver halide grains and emulsions indicates that chloride is present in a concentration of greater than 50 mole percent, based on total silver.
In referring to grains and emulsions containing two or more halides, the halides are named in order of ascending concentrations.
All references to the periodic table of elements periods and groups 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.
The term “cubic grain” is employed to indicate a grain is that bounded by six {100} crystal faces. Typically the comers 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 “tabular grain” indicates a grain having two parallel major crystal faces (face which are clearly larger than any remaining crystal face) and having an aspect ratio of at least 2.
The term “aspect ratio” designates the ratio of the equivalent circular diameter of a major face to grain thickness.
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 “{100} tabular” is employed in referring to tabular grains and tabular grain emulsions in which the tabular grains have {100} major faces.
The term “equivalent spherical diameter” in referring to silver halide grains refers to the diameter of a sphere which has the same volume of an individual grain.
The term “central portion” in referring to silver halide grains refers to that portion of the grain structure that is first precipitated accounting for up to 99 percent of total precipitated silver required to form the grains.
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 “surface modifier” refers to any material other than silver ion or halide ion that is associated with a portion of the silver halide grains other than the central portion.
The term “log E” is the logarithm of exposure in lux-seconds.
Speed is reported as relative log speed, where 1.0 relative log speed units 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 “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.
BACKGROUND
In its most commonly practiced form silver halide photography employs a film in a camera to produce, following photographic processing, a negative image on a transparent film support. A positive image for viewing is produced by exposing a photographic print element containing one or more silver halide emulsion layers coated on a reflective white support through the negative image in the camera film, followed by photographic processing. Whereas high bromide silver halide emulsions are the overwhelming commercial choice for camera films, high chloride grain emulsions are the overwhelming commercial choice for photographic print elements. In a relatively recent variation negative image information is retrieved by scanning and stored in digital form. The digital image information is later used to expose imagewise the emulsion layer or layers of the photographic print element. Whether a conventional optical or a digital image printing exposure is employed, it is desired in high chloride emulsions for color paper applications to obtain high photographic speed at the desired sensitometric curve shape.
A typical example of imaging systems which require that a hard copy be provided from an image which is in digital form is electronic printing of photographic images which involves control of individual pixel exposure. Such a system provides greater flexibility and the opportunity for improved print quality in comparison to optical methods of photographic printing. In a typical electronic printing method, an original image is first scanned to create a digital representation of the original scene. The data obtained is usually electronically enhanced to achieve desired effects such as increased image sharpness, reduced graininess and color correction. The exposure data is then provided to an electronic printer which reconstructs the data into a photographic print by means of small discrete elements (pixels) that together constitute an image. In a conventional electronic printing method, the recording element is scanned by one or more high energy beams to provide a short duration exposure in a pixel-by-pixel mode using a suitable source, such as a light emitting diode (LED) or laser. A cathode ray tube (CRT) is also sometimes used as a printer light source in some devices. Such methods are described in the patent literature, including, for example, Hioki U.S. Pat. No. 5,126,235; European Patent Application 479 167 A1 and European Patent Application 502 508 A1. Also, many of the basic principles of electronic printing are provided in Hunt, The
Reproduction of Colour
, Fourth Edition, pages 306-307, (1987). Budz et al U.S. Pat. No. 5,451,490 discloses an improved electronic printing method which comprises subjecting a radiation sensitive silver halide emulsion layer of a recording element to actinic radiation of at least 10
−4
ergs/cm
2
for up to 100 &mgr; seconds duration in a pixel-by-pixel mode. The radiation sensitive silver halide emulsion layer contains a silver halide grain population comprising at least 50 mole percent chloride, based on silver, forming the grain population projected area. At least 50 percent of the grain population projected area is accounted for by tabular grains that are bounded by {100} major faces having adjacent edge ratios of less than 10, each having an aspect ratio of at least 2. The substitution of a high chloride tabular grain emulsion for a high chloride cubic grain emulsion was demonstrated to reduce high intensity reciprocity failure (HIRF).
Electronic digital printing onto silver halide media frequently is subject to the appearance of various digital printing artifacts. Image artifacts which may be associated with optical scan printing on silver halide media include “digital fringing”, “contouring”, and “banding”. Of the artifacts associated with printing digital images onto silver halide media, “digital fringing”, or the formation of visually soft edges, especially around text, probably elicits the greatest objections. This artifact pertains to unwa
Bell Eric L.
Ferguson Pamela M.
Mydlarz Jerzy Z.
Anderson Andrew J.
Eastman Kodak Company
Walke Amanda C.
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