Radiation imagery chemistry: process – composition – or product th – Color imaging process – Laser or radiation exposure other than visible light
Reexamination Certificate
1999-12-30
2001-06-19
Baxter, Janet (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Color imaging process
Laser or radiation exposure other than visible light
C430S569000, C430S567000
Reexamination Certificate
active
06248507
ABSTRACT:
FIELD OF THE INVENTION
This invention is directed to radiation sensitive cubical silver iodochloride emulsions having epitaxially deposited silver bromide, and a process for the preparation thereof.
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.
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 “central portion” in referring to cubical silver halide grains refers to that portion of the grain structure that is first precipitated accounting for up to 98 percent of total precipitated silver required to form the {100} crystal faces of 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 “normalized” molar addition rate hereinafter assigned the symbol R
n
is a measure of the intensity of rate of addition of silver salt solution to the reaction vessel in case of a double-jet precipitation process. R
n
is defined by the formula:
R
n
=Q
f
C
f
/M
where Q
f
is the volumetric rate (liters/min) of addition of silver salt solution into the reaction vessel, C
f
is the molar concentration (moles/liter) of the said solution, and M is total moles of silver halide host grains in the reaction vessel at the precise moment of above addition.
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 “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 “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. 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.
Whereas high bromide silver halide emulsions are the overwhelming commercial choice for camera films, high chloride cubic grain emulsions are the overwhelming commercial choice for photographic print elements. It is desired in high chloride emulsions for color paper applications to obtain high photographic speed at the desired curve shape. While it has been common practice to avoid or minimize the incorporation of iodide into high chloride grains employed in color paper, it has been recently observed that silver iodochloride cubical grains can offer exceptional levels of photographic speed where iodide is incorporated in such emulsion gains in a profiled manner. Chen et. al. in U.S. Pat. No. 5,547,827; Chen et. al. in U.S. Pat. No. 5,550,013; Chen et. al. in U.S. Pat. No. 5,605,789; Chen et. al. in U.S. Pat. No. 5,726,005; Edwards et.al. in U.S. Pat. No. 5,728,516; Chen et. al. in U.S. Pat. No. 5,736,310; Budz et.al. in U.S. Pat. No. 5,783,372 and Edwards et.al. in U.S. Pat. No. 5,792,601 disclose highly sensitive silver iodochloride cubical emulsions with low levels of iodide located in the exterior portions of the grains. The interior portions of such grains can be prepared by employing any convenient high chloride cubical grain precipitation procedure. The emulsion grains thus formed then serve as hosts for further growth. Once a host grain population has been prepared, an increased concentration of iodide is introduced into the emulsion to form the region of the grains containing maximum iodide concentration. The source of iodide ion can be silver iodide grains or any iodide-releasing agent, but it is typically disclosed that iodide is preferably introduced alone as an aqueous solution of an alkali metal iodide salt. This is followed by double-jet introduction of silver nitrate and alkali metal chloride solutions at conventional molar addition rates, constant or ramped, till the exterior portion is grown to the desired size.
Many known imaging systems require that a hard copy be provided from an image which is in digital form. A typical example of such a system 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 cathode ray tube (CRT), light emitting diode (LED) or laser. 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).
Reciprocity characteristics, usually referred to as reciprocity failure, are measured in terms of departures from the law of photographic reciprocity. The exposure (E) of a photographic element is the product of the intensity (I) of exposure multiplied by its duration (time):
E=I×time
According to the photographic law of reciprocity,
Budz Jerzy A.
Jagannathan Seshadri
Sadler Alan R.
Anderson Andrew J.
Baxter Janet
Eastman Kodak Company
Walke Amanda C.
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