# US 4,395,483 A · Direct positive type silver halide photosensitive material

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- Number: US 4,395,483 A
- Document ID: US4395483A
- Status: Granted
- Kind: A
- Application number: 06/352,928
- Filed: 1982-02-26
- Granted: 1983-07-26
- Earliest claimed: 1979-04-27
- Assignees: Fuji Photo Film Co., Ltd.
- Inventors: Terumi Matsuda; Shoji Ishiguro; Shigenori Moriuchi; Yoshiaki Suzuki
- Web page: https://patentgrep.com/patent/US4395483A

## CPC

- G03C 1/48523: {characterised by the desensitiser}
- Y10S 430/137: Cobalt complex containing
- G03C: PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES (for photomechanical purposes G03F); PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY (photographic processes characterised by the use or manipulation of apparatus classifiable per se in subclass G03B, see G03B; photomechanical production of textured or patterned surfaces G03F; electrophotography, magnetography G03G)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A high contrast, chemically fogged direct positive type silver halide photosensitive material is described containing at least one ammine complex salt selected from those including cobalt, nickel, ruthenium or chromium, by which the contrast in the lower optical density region is improved while retaining superior Dmax and sensitivity.

## Claims

### Claim 1

A direct positive type silver halide photosensitive material for obtaining a high contrast image in the highlight portions thereof, said image comprised substantially of only silver prepared by:
(a) chemically fogging silver halide grains, and
(b) subsequent to said fogging, adding at least one metal ammine complex salt in an amount of 10.sup.-5 to 10.sup.-2 mol per mol of silver wherein the metal component is selected from the group consisting of cobalt, nickel, ruthenium and chromium.

### Claim 2 (depends on 1)

A direct positive type silver halide photosensitive material according to claim 1, wherein the metal of the metal ammine complex salt is selected from the group consisting of Co.sup.3+, Cr.sup.3+, Ni.sup.2+, and Ru.sup.3+.

### Claim 3 (depends on 1)

A direct positive type silver halide photosensitive material according to claim 1, wherein the metal ammine complex salt comprises from 4 to 6 ammine groups.

### Claim 4 (depends on 1, 2)

A direct positive type silver halide photosensitive material according to claim 1, 2, or 3, wherein said material does not contain a compound which will form a color dye image.

### Claim 5 (depends on 1, 2)

A direct positive type silver halide photosensitive material according to claim 1, 2, or 3, in which the metal ammine complex salt is a cobalt ammine complex salt.

### Claim 6 (depends on 1, 2)

A direct positive type silver halide photosensitive material according to claim 1, 2, or 3, including a sensitizing organic dye consisting of an electron acceptor having an E.sub.red of at least -0.1.

### Claim 7 (depends on 6)

A direct positive type silver halide photosensitive material according to claim 6, in which the sensitizing organic dye is at least one member selected from the dyes of the formulae (I), (II), (III), (IV), (V) and (VI): ##STR8## wherein R.sup.1 represents a hydrogen atom or a nitro group; R.sup.2 is selected from a hydrogen atom, lower alkyl groups, a chlorine atom, a carboxyl group, lower alkoxycarbonyl groups and aryl groups; R.sup.3 is selected from a hydrogen atom, alkyl groups, substituted alkyl groups and aryl groups; R.sup.4 is selected from alkyl groups, substituted alkyl groups and aryl groups; L.sup.1 and L.sup.2 each represents a methine chain or L.sup.2 and R.sup.4 together can form a polymethine chain; X.sub.1 represents an anion; m and n each represents 1 or 2; and Z represents an atomic group forming a 5-membered or 6-membered heterocyclic nucleus; ##STR9## ##STR10## wherein in formulae (II) and (III) m represents 1 or 2; n represents 1 or 2; r represents 1, 2 or 3; p represents 1, 2, 3 or 4; L.sup.3 and L.sup.4 each represents a methine chain, or L.sub.3 and R.sup.5 can together form a polymethylene chain; R.sup.5 and R.sup.7 are each selected from alkyl groups, substituted alkyl groups and a vinylmethyl group; R.sup.6 represents a substituent common in the pyrazolo[1,5-a]benzimidazole compounds, such as a hydrogen atom, an alkyl group, a carboxyl group, an alkoxycarbonyl group, an amino group, an acylamino group, an aryl group, and an acid amino group; Z.sup.1 represents an atomic group forming a 5-membered or 6-membered heterocyclic nucleus and is the same as Z in formula (I); Q represents a known substituent in pyrazolo[1,5-a]benzimidazole compounds, such as a halogen atom, a lower alkyl group, an aryl group, a carboxyl group, an alkoxycarbonyl group, or an acylamino group; and X.sub.2 represents an anion as defined for X.sub.1 ; ##STR11## wherein Z.sup.2 represents an atomic group forming a cycloheptatriene ring; Y represents an oxygen atom, --NH-- or --N.dbd.; A represents .dbd.0, a halogen atom or a pyridinium group; and B represents a hydrogen atom or an alkoxycarbonyl group, or ##STR12## wherein L.sup.1, L.sup.2, Z, R.sup.4, n, m and X.sub.1 are as defined in the formula (I); ##STR13## wherein Z, R.sup.4, m, n and X.sub.1 are as defined in formula (I), and a represents 1 or 2.

### Claim 8 (depends on 1)

A direct positive type silver halide photosensitive material according to claim 1, wherein the amount of said metal ammine complex salt is 10.sup.-4 to 10.sup.-3 mol per mol of silver.

### Claim 9 (depends on 1, 2)

A direct positive type silver halide photosensitive material as in claim 1, 2, or 3, wherein the particle size of the silver halide comprising the photosensitive material is from 0.04 to 2.0.mu. in diameter.

### Claim 10 (depends on 9)

A direct positive type silver halide photosensitive material as in claim 9, wherein the particle size of the silver halide comprising the photosensitive material is from 0.15 to 0.70.mu. in diameter.

### Claim 11 (depends on 7)

A direct positive type silver halide photosensitive material according to claim 7, wherein the sensitizing organic dye is present in an amount from about 1.times.10.sup.-6 to 5.times.10.sup.-3 mol per mol of silver halide.

### Claim 12

A process for preparing a direct positive type silver halide emulsion for obtaining a high contrast image in the highlight portions thereof, said image comprised substantially of only silver comprising:
(1) chemically fogging silver halide grains containing at least 40 mol% silver chloride;
(2) adsorbing a sensitizing organic dye onto the surfaces of the chemically fogged grains; and
(3) subsequent to said fogging step, adding at least one member selected from the group consisting of metal ammine complex salts of cobalt, nickel, ruthenium and chromium in an amount of 10.sup.-5 to 10.sup.-2 mol per mole of silver halide.

### Claim 13 (depends on 12)

A process for preparing a direct positive type silver halide emulsion as in claim 12, wherein the metal of the metal ammine complex salt is selected from the group consisting of Co.sup.3+, Cr.sup.3+, Ni.sup.2+, and Ru.sup.3+.

### Claim 14 (depends on 12)

A process for preparing a direct positive type silver halide emulsion as in claim 12, wherein the metal ammine complex salt comprises from 4 to 6 ammine groups.

### Claim 15 (depends on 12, 13)

A process as claimed in any of claim 12 or 13, wherein said metal ammine complex salt is a cobalt amine complex salt.

### Claim 16 (depends on 12)

A process for preparing a direct positive type silver halide emulsion according to claim 12, wherein the metal ammine complex salt is added in an amount of 10.sup.-4 to 10.sup.-3 mol per mol of silver.

### Claim 17

A process for forming a silver image of high contrast in the highlight portions thereof, comprising:
preparing a high contrast, chemically fogged direct positive type silver halide photosensitive material by chemically fogging silver halide grains and subsequent to said fogging, adding at least one metal ammine complex salt in an amount of 10.sup.-5 to 10.sup.-2 mol per mol of silver selected from the group consisting of cobalt, nickel, lithium, and chromium; and
imagewise exposing said high contrast, chemically fogged direct positive type silver halide photosensitive material; and
developing said material to form a silver image said image being comprised substantially of only silver.