PHOTOGRAPHIC SILVER HALIDE LIGHT-SENSITIVE MATERIALS
United States Patent 3790390
A silver halide photographic light-sensitive material wherein one emulsion layer contains silver halide grains with a mean grain size no larger than 0.9 microns, at least one group VIII metal compound, and at least one sensitizing dye of the formula: ##SPC1## Wherein Z, R, R1, L1 and L2 are as defined in the specification.
US Patent References:
Photographic emulsion
Brooker - April 1937 - 2078233
Photographic emulsions sensitized with salts of metals of group viii of the periodicarrangement of the elements
Smith et al. - August 1948 - 2448060
Complex compounds of the platinum group as photographic fog inhibitors
Trivelli et al. - August 1951 - 2566245
LIGHT-SENSITIVE MATERIALS OPTICALLY SENSITIZED WITH CHLOROPROPYLSULFONIC ACID SUBSTITUTED MEROCYANINES
Kampfer et al. - November 1969 - 3480439
Photographic emulsion
Brooker - April 1937 - 2078233
Photographic emulsions sensitized with salts of metals of group viii of the periodicarrangement of the elements
Smith et al. - August 1948 - 2448060
Complex compounds of the platinum group as photographic fog inhibitors
Trivelli et al. - August 1951 - 2566245
LIGHT-SENSITIVE MATERIALS OPTICALLY SENSITIZED WITH CHLOROPROPYLSULFONIC ACID SUBSTITUTED MEROCYANINES
Kampfer et al. - November 1969 - 3480439
Inventors:
Shiba, Keisuke (Kanagawa, JA)
Hinata, Masanao (Kanagawa, JA)
Yamasue, Koutarou (Kanagawa, JA)
Sato, Akira (Kanagawa, JA)
Ikeda, Tadashi (Kanagawa, JA)
Hinata, Masanao (Kanagawa, JA)
Yamasue, Koutarou (Kanagawa, JA)
Sato, Akira (Kanagawa, JA)
Ikeda, Tadashi (Kanagawa, JA)
Application Number:
05/214216
Publication Date:
02/05/1974
Filing Date:
12/30/1971
View Patent Images:
Export Citation:
Assignee:
Fuji Photo Film Co., Ltd. (Kanagawa, JA)
Primary Class:
Other Classes:
430/592, 548/226, 548/215, 430/611
International Classes:
G03C1/09; G03C1/22; G03C1/12; G03C1/08
Field of Search:
96/125,108,140
Primary Examiner:
Brown, Travis J.
Attorney, Agent or Firm:
Richard, Sughrue Et Al C.
Claims:
1. A silver halide photographic emulsion comprising light-sensitive silver halide grains whose mean grain size by diameter is no greater than 0.9 micron; 10-6 to 10-3 mol of at least one of the compounds of the group VIII metals in the periodic table per 1 gram mol of said silver halide; and at least one of the sensitizing dyes represented by the following general formula: ##SPC4##
2. A silver halide photographic emulsion as claimed in claim 1 wherein Y in
3. A silver halide photographic emulsion as claimed in claim 1 wherein the alkyl group of R, R1, or Ro is a hydroxy alkyl group, an acetoxyalkyl group, an alkoxyalkyl group, a carboxy group-containing alkyl group, a sulfo group-containing alkyl group, an aralkyl group, or an allyl group, wherein the aryl group of Ro is an alkoxy phenyl or a
4. A silver halide photographic emulsion as claimed in claim 1 wherein the
5. A silver halide photographic emulsion as claimed in claim 1 wherein the
6. A silver halide photographic emulsion as claimed in claim 1 wherein the
7. A silver halide photographic emulsion as claimed in claim 7 wherein the
8. A silver halide photographic emulsion as claimed in claim 1 wherein the emulsion further contains 2-mercaptobenzimidazole, 1-phenyl-5-mercaptotetrazole or 5-methyl-7-hydroxy-1,3,4-triazoindolizine.
9. A silver halide photographic emulsion as claimed in claim 1 wherein the sensitizing dye is chosen from the group consisting of ##SPC5##
10. A silver halide photographic emulsion as claimed in claim 3, wherein said hydroxyalkyl group is chosen from the group consisting of
11. A silver halide photographic emulsion as claimed in claim 3, wherein said acetoxyalkyl group is chosen from the group consisting of
12. A silver halide photographic emulsion as claimed in claim 3, wherein
13. A silver halide photographic emulsion as claimed in claim 3, wherein said carboxy group containing alkyl group is selected from the group consisting of carboxymethyl, 2-carboxyethyl, 3-carboxypropyl, and
14. A silver halide photographic cmulsion as claimed in claim 3, wherein said sulfo-group containing alkyl group is selected from the group consisting of 2-sulfoethyl, 3-sulfopropyl, 4-sulfobutyl, 2-hydroxy-1-sulfopropyl, 2-(3-sulfopropoxy) ethyl, 2-acetoxy-1-sulfopropyl, 3-methoxy-2-(3-sulfopropoxy) propyl, 2-[2-(3-sulfopropoxy) ethoxy] ethyl, and 2-hydroxy-3-(3'-sulfopropoxy)
15. A silver halide photographic emulsion as claimed in claim 3, wherein said aralkyl group is selected from the group consisting of benzyl, phenethyl, p-sulfobenzyl, and p-carboxybenzyl.
2. A silver halide photographic emulsion as claimed in claim 1 wherein Y in
3. A silver halide photographic emulsion as claimed in claim 1 wherein the alkyl group of R, R1, or Ro is a hydroxy alkyl group, an acetoxyalkyl group, an alkoxyalkyl group, a carboxy group-containing alkyl group, a sulfo group-containing alkyl group, an aralkyl group, or an allyl group, wherein the aryl group of Ro is an alkoxy phenyl or a
4. A silver halide photographic emulsion as claimed in claim 1 wherein the
5. A silver halide photographic emulsion as claimed in claim 1 wherein the
6. A silver halide photographic emulsion as claimed in claim 1 wherein the
7. A silver halide photographic emulsion as claimed in claim 7 wherein the
8. A silver halide photographic emulsion as claimed in claim 1 wherein the emulsion further contains 2-mercaptobenzimidazole, 1-phenyl-5-mercaptotetrazole or 5-methyl-7-hydroxy-1,3,4-triazoindolizine.
9. A silver halide photographic emulsion as claimed in claim 1 wherein the sensitizing dye is chosen from the group consisting of ##SPC5##
10. A silver halide photographic emulsion as claimed in claim 3, wherein said hydroxyalkyl group is chosen from the group consisting of
11. A silver halide photographic emulsion as claimed in claim 3, wherein said acetoxyalkyl group is chosen from the group consisting of
12. A silver halide photographic emulsion as claimed in claim 3, wherein
13. A silver halide photographic emulsion as claimed in claim 3, wherein said carboxy group containing alkyl group is selected from the group consisting of carboxymethyl, 2-carboxyethyl, 3-carboxypropyl, and
14. A silver halide photographic cmulsion as claimed in claim 3, wherein said sulfo-group containing alkyl group is selected from the group consisting of 2-sulfoethyl, 3-sulfopropyl, 4-sulfobutyl, 2-hydroxy-1-sulfopropyl, 2-(3-sulfopropoxy) ethyl, 2-acetoxy-1-sulfopropyl, 3-methoxy-2-(3-sulfopropoxy) propyl, 2-[2-(3-sulfopropoxy) ethoxy] ethyl, and 2-hydroxy-3-(3'-sulfopropoxy)
15. A silver halide photographic emulsion as claimed in claim 3, wherein said aralkyl group is selected from the group consisting of benzyl, phenethyl, p-sulfobenzyl, and p-carboxybenzyl.
Description:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a silver halide photographic emulsion, more particularly to a silver halide photographic light-sensitive material having high sensitivity to blue light in "flashlight exposure," which term is defined in the following explanation.
2. Description of the Prior Art
With the advent of what has been called the information age, various systems for rapidly communicating information have been developed. For example, there are press facsimile systems for rapidly sending newspaper manuscripts to remote places, high speed photographic typesetting systems for rapid typesetting, cathode ray-tube display systems for indicating the information output of a computer in letters or in patterns, and the like.
In these instruments for rapidly communicating information, short-time exposure, less than 1/100,000 second, sometimes as short as about 1/1,000,000 second, is often employed. Recently, the light-sensitive materials for use with such instruments have been more and more in demand.
As light sources used in these instruments, there have been used combinations of light sources having high illuminance, such as a xenon arc lamp, and high speed shutters; xenon flash light sources; and cathode ray-tube light sources. Amount these, cathode ray-tubes, especially those having fluorescent substance with short-time afterglow, are generally used for flying spot. For example, various fluorescent substances referred to as "P-15," "P-11," "P-16," "P-24 ," etc., are used, all of which are well known to one of ordinary skill in the art, Among these, P-15, P-11, P-16, and P-24 are known to have their maximum spectral energy distribution of emission at 505 nm, 460 nm, 385 nm and 520 nm, respectively. It is necessary in a light-sensitive material for recording images formed on a cathode ray-tube wherein these various kinds of fluorescent substances are used to have a high sensitivity in at least the blue light-sensitive region, especially at the wavelengths of from 380 to 520 nm.
The afterglow time of the emission of the aforesaid cathode ray-tube is usually as short as 1/10,000,000 to 1/100,000 second. Xenon flash lamps having an emission time similarly short are frequently used. In the present specification, the above-mentioned short-time exposure by a light source of this kind is generically referred to as "flashlight exposure."
The room wherein such light-sensitive materials are used is generally comparatively bright so that the operation can be conducted with ease. These materials are often used under comparatively bright yellowish-green safety light such as a Fuji Safe Light No. 2A (the percent transmission curve thereof is given in the drawing), and hence light-sensitive materials having a low sensitivity to safety lights of this kind are desirable.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a silver halide light-sensitive material having a high sensitivity to blue light in flashlight exposure.
Another object of the present invention is to provide a light-sensitive material having high sensitivity to blue light which is capable of being dealt with under bright yellowish-green safety light.
The blue-light-sensitive region (mainly the wavelength region of from 380 to 520 nm) corresponds to the light-sensitive region intrinsic to silver halide. In order to obtain a silver halide emulsion having high intrinsic sensitivity in flashlight exposure, processes for increasing the sensitivity by making the grain size of the silver halide large, processes for increasing the sensitivity by chemical sensitization, etc., were investigated. However, in the process comprising making the grain size large, the granular properties and the sharpness of the image formed were greatly deteriorated. In the process of chemical sensitization, the stability thereof to the safety light was deteriorated. In addition, when the sensitivity of the silver halide was increased by chemical sensitization in flashlight exposure, the storage stability thereof was deteriorated and, for example, undesirable fogs or stains were observed.
The objects of the present invention were attained by using a silver halide emulsion containing light-sensitive silver halide grains whose mean grain size by diameter (and by number) is equal to or smaller than 0.9 micron; at least one compound containing a group VIII metal in the periodic table in an amount of 10 - 6 to 10 - 3 mol per 1 gram mol of the silver halide; and at least one sensitizing dye represented by the general formula: ##SPC2##
wherein R and R 1 each represents a hydrogen atom, an alkyl group, a substituted alkyl group or an aryl group, Y represents an oxygen atom or N--R o (R o being a hydrogen atom, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group or an allyl group), L 1 and L 2 each represents a methine group and Z represents the non-metallic atoms necessary to complete a series of oxazoline nuclei; in a binder such as gelatin.
BRIEF DESCRIPTION OF THE DRAWING
The drawing is the percent transmission curve of a bright yellowish-green safety light.
DETAILED DESCRIPTION OF THE INVENTION
To explain more particularly about the general formula above R and R 1 each represents a hydrogen atom, an alkyl group i.e., unsubstituted alkyl group and substituted alkyl group usually used for sensitizing dyes) such as methyl, ethyl, n-propyl, etc., hydroxy alkyl (e.g., 2-hydroxyethyl, 4-hydroxybutyl), acetoxy alkyl (e.g., 2-acetoxyethyl, 3-acetoxypropyl), alkoxy alkyl (e.g., 2-methoxyethyl), carboxy groups containing alkyl (e.g., carboxymethyl, 2-carboxyethyl, 3-carboxypropyl, 2-(2-carboxyethoxy) ethyl), sulfo group containing alkyl (e.g., 2-sulfoethyl, 3-sulfopropyl, 4-sulfobutyl, 2-hydroxy-1-sulfopropyl, 2-(3-sulfopropoxy)ethyl, 2-acetoxy-1-sulfopropyl, 3-methoxy-2-(3-sulfopropoxy)propyl, 2-[2-(3-sulfopropoxy) ethoxy]ethyl, 2-hydroxy-3--(3'-sulfopropoxy) propyl), aralkyl (e.g., benzyl, phenethyl, p-sulfobenzyl, p-carboxybenzyl), allyl group, etc., or an aryl group such as phenyl, preferred carbon atom range of said alkyl moiety being up to 8; Y represents an oxygen atom or N--R o (wherein R o represents a hydrogen atom, the same alkyl group as R and R 1 , an aryl group (i.e. unsubstituted aryl group and substituted aryl group) such as phenyl, tolyl, naphthyl, etc., alkoxy phenyl (e.g., methoxyphenyl), halogenophenyl (e.g., chlorophenyl), etc.), L 1 and L 2 each represents a methine group preferably having up to 8 carbon atoms such as =CH--, =C(CH 3 )--, =C(C 2 H 5 )--, =C(C 6 H 5 )--, etc., and Z represents the non-metallic atoms necessary to complete a series of oxazoline nuclei such as the oxazoline nucleus, 4- and/or 5- alkyl substituted oxazoline nucleus (e.g., 4,4-dimethyloxazoline nucleus, 5-methyloxazoline nucleus, etc.), 4- and/or 5-phenyl substituted oxazoline nucleus (e.g., 4,5-diphenyloxazoline nucleus).
The sensitizing dyes used in the present invention are known and are described, for example, in British Pat. No. 1,074,433, and can be readily synthesized by reference to said specification.
Examples of dyes represented by the general formula are set out below, but the dyes used in the present invention are not to be thereby limited. ##SPC3##
(A mean grain size by diameter is designed hereinafter simply as "a mean grain size").
As a support in the present invention, there can be used glass, metal plates, wooden plates, baryta paper, cellulose derivative films, films of synthetic resins, synthetic papers, polyolefin-coated papers, and the like.
As a binder, water-soluble film-forming high molecular weight materials such as gelatin, polyvinyl alcohol, polyvinyl pyrrolidone, sodium alginate, carboxymethyl cellulose, etc., can be used separately or in combination. As the light-sensitive silver halide, there can be used silver chloride, silver bromide, silver chlorobromide, silver bromoiodide, etc. The grain size of the silver halide is, more effectively, smaller than 0.8 micron, most especially not larger than 0.6 micron, on the average.
The production of the light-sensitive silver halide grain, that is, the production of the silver halide emulsion, comprising forming the crystals of silver halide grains in a dispersed state in the binder, and developing the crystals into a suitable grain size, is conducted according to conventional methods.
The group VIII metals of the periodic table include iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum and, as the compounds containing these metals which are most preferably used in the present invention, there are iron, iridium and rhodium compounds. As examples of the group VIII metal compounds according to this invention, there are ferrous sulfate FeSO 4 . 5H 2 0; ferric chloride FeCl 3 ; potassium hexacyanoferrate (II) K 4 Fe(CN) 6 . 3H 2 O; potassium hexacyanoferrate (III) K 3 Fe(CN) 6 : cobaltous chloride CoCl 2 ; cobaltous nitrate Co(NO 3 ) 2 . 6H 2 O; potassium hexacyanocobaltate (III) K 3 Co(CN) 6 ; nickelous chloride NiCl 2 . 6H 2 O; nickel (II) nitrate Ni(NO 3 ) 2 . 6H 2 O; ruthenium (III) chloride RuCl 3 ; potassium hexachlororuthenate (IV) K 2 RuCl 6 ; rhodium (III) chloride RhCl 3 . 4H 2 O; ammonium hexachlororhodate (III) (NH 3 ) 3 RhCl 6 ; palladium (II) chloride PdCl 2 ; palladium (II) nitrate Pd(NO 3 ) 2 ; palladium (II) bromide PdBr 2 ; potassium hexachloropalladate (IV) K 2 PdCl 6 ; potassium tetrathiocyanatopalladate (II) K 2 Pd(CNS) 4 ; osmium (II) chloride OsCl 2 ; iridium (III) chloride IrCl 3 ; iridium (IV) chloride IrCl 4 ; iridium (III) bromide IrBr 3 . 4H 2 O; iridium (IV) bromide IrBr 4 ; potassium hexachloroiridate (III) K 3 IrCl 6 ; potassium hexachloroiridate (IV) K 2 IrCl 6 ; ammonium hexachloroplatinate (IV) (NH 4 ) 2 PtCl 6 ; potassium hexachloroplatinate (IV) K 2 PtCl 6 ; ammonium hexabromoplatinate (IV) (NH 4 ) 2 PtBr 6 ; and the like. These group VIII metal compounds are used in an amount of 10 - 6 mol to 10 - 3 mol per 1 mol of silver halide, independently or in combinations of more than one of these compounds. A gold compound can be preferably added to the emulsion in combination with any of those compounds of the group VIII metal. The addition of these compounds is properly conducted at the formation of the silver halide grains, at the start of the ripening of the emulsion or in the course thereof in the production of the silver halide emulsion. Otherwise, they may be added, before coating the ripened emulsion on a support, to the emulsion together with a known stabilizer such as 2-mercaptobenzimidazole, 1-phenyl-5-mercaptotetrazole, 5-methyl7-hydroxy-1,3,4-triazoindolizene, etc., antifogging agents, toning agents, coating assistants such as sodium alkylbenzenesulfonate, saponin, etc., plasticizers, hardeners such as formaldehyde, mucochloric acid, delustering agents, development accelerators, fluorescent brightening agents, color couplers or developing agents for activator development, etc. These materials are added, when desired, for their art-recognized function.
The sensitizing dyes used in the present invention are used in an amount of 10 - 5 to 10 - 2 mol per mol of silver halide contained in the silver halide emulsion, either separately or in combinations of more than one of them. The addition of the sensitizing dyes to the emulsion is carried out in the same manner as the aforesaid metal compounds. They may be added to the emulsion simultaneously with the said metal compounds, or may be added independently regardless of the order.
After the flashlight exposure, the light-sensitive material prepared in this way can be developed and fixed in the conventional manner, or may be treated in the manner generally known as the diffusion transfer process, or may be treated according to the developing process known as activator development (a process comprising developing a light-sensitive material containing a developing agent with a solution containing alkaline material without developing agent) by previously adding a sufficient amount of a developing agent to the light-sensitive layer.
It has been known that, regardless of the existence of the above-mentioned metal compounds, the sensitizing dyes represented by the general formula are capable of spectrally sensitizing light-sensitive materials. As the result of various experiments in flashlight exposure, the sensitizing effect of the emulsion not containing above-mentioned metal compounds is small while in the usual exposure, the emulsion not containing said metal compounds shows at least about the same sensitizing effect as that of the emulsion containing said metal compounds. However, surprisingly, in the emulsion containing the group VIII metal compounds of the present invention, a remarkable sensitizing effect is produced as is shown in the following examples. On the other hand, the light-sensitive material whose sensitivity in flashlight exposure is increased by chemical sensitization or by the process whereby the grain size is made larger, has an increased sensitivity to safety light, and under a safety light is deteriorated, as is shown in the following examples. Especially, the mean grain size of the silver halide is quite important for use under a safe light, and the mean grain size of the silver halide is advantageously not larger than 0.9 micron.
A bright safety light is desirable and it is the prerequisite for the light-sensitive material used in the present invention that it can be safely dealt with under a yellowish-green safety light, and hence it can of course be dealt with under red light, such as a Fuji Safe Light No. 2, or under the light passed through a safety light filter which transmits light of longer wavelengths.
It has long been known that, when added to a photographic emulsion, the above-mentioned metal compounds exhibit various effects. As is described in U.S. Pat. 2,448,060, when hexahalogenoruthenate (III), hexahalogenorhodate (IV), hexahalogenopalladate (IV), hexahalogenoosmate (IV), hexahalogenoiridate (IV), hexahalogenoplatinate (IV), etc., are added to a silver halide emulsion upon ripening, the intrinsic sensitivity of the light-sensitive material wherein this emulsion is used increases and, as is described in U.S. Pat. No. 2,566,245, when said compounds are added to a silver halide emulsion in large amounts, the storage stability of the light-sensitive material obtained under the circumstances of high temperature and high humidity is improved. Furthermore, it is described that potassium hexacyanocobaltate (III) (see U.S. Pat. No. 2,517,541) or rhodium trichloride (see FIAT report No. 360) are capable of making the resulting light-sensitive material high-contrast (i.e. high gamma value) when added to a silver halide emulsion.
The group VIII metal compounds used in the present invention are added only for the object of the present invention; however, the above-mentioned various photographic effects may be obtained at the same time. In addition, as described in British Pat. No. 570,393, a process comprising adding a gold compound upon ripening to raise the intrinsic sensitivity of the light-sensitive material can also be applied.
The present invention will now be further illustrated in more detail by the following examples.
EXAMPLE 1
A silver bromoiodide emulsion (containing 2 mol percent of AgI) of about 0.6 micron mean grain size, not containing the compounds of a group VIII metal (hereinafter referred to merely as a "metal compound" in the examples) [control emulsion (I) ], was prepared in the presence of 1 × 10 - 1 mol of ammonia per 1 mol of silver halide, and an emulsion having about the same sensitivity as that of the control emulsion (I) was prepared with the same prescription with adding 3 × 10 - 6 mol of ammonium hexachlororhodate (III) per 1 mol of silver halide contained in the said emulsion upon forming the silver halide grains and further adding 2 × 10 - 5 mol of potassium chloroplatinate per 1 mol of silver halide upon post-ripening. Each of these two emulsions was divided into two portions, then 6 × 10 -3 mol of the Dye 1 per 1 mol of silver halide contained in the emulsion was added to one portion, leaving the other portion as such. In addition, 2-mercaptobenzimidazole was added thereto as a stabilizer, mucochloric acid as a hardener, and saponin as a coating assistant, and the emulsion was then coated on a polyethylene terephthalate (PET) film.
On the other hand, 8 × 10 - 1 mol of ammonia per 1 mol of silver halide was added upon precipitating the silver halide to prepare an emulsion of 0.95 micron mean grain size (containing the above-mentioned metal compound, but free from the dye), and the emulsion coated on a PET film base (which corresponds to control emulsion (I')).
The above-described samples were imagewise exposed for 1/100 and 1/1,000,000 second using a Mark III sensitometer made by EG G Co. in the U.S.A. The exposed samples were developed with the following developer for 3 minutes at 20° C.
______________________________________ Metol 8 g Sodium Carbonate (monohydrate) 150 g Hydroquinone 30 g Potassium Bromide 7 g Water to make up 1 liter ______________________________________
After fixing, washing and drying, the transmission density was measured. The sensitivity value was determined as the reciprocal of the quantity of light which gave a density of 2.5. The sensitivity of the control emulsion (I) was calculated as 100, and the relative sensitivities of the other emulsions based on that of the control emulsion (I) are given in Table 1.
In addition, the fog density value obtained by leaving the samples under a Fuji No. 2A Safe Light (20W) at a distance of 1 m for 1 minute and 20 minutes, and then developing them with the above-described developer, was also measured.
TABLE 1 ______________________________________ Sensitivity exposed for 1/100 sec. Sensitivity exposed for 1/1,000,000 sec. Fog when exposed to No. 2A Safe Light for: 1 min. 20 min. ______________________________________ Control emulsion (I) 100 100 0.0 0.03 Control emulsion (I) + the group VIII metal 98 100 0.0 0.02 Control emulsion (I) + Dye 1 130 110 0.0 0.04 Control emulsion (I) + the group VIII metal + Dye 1 120 150 0.0 0.01 Control emulsion (I') 150 150 0.01 1.00 ______________________________________
As is obvious from Table 1, the sensitivity of the emulsion to flashlight is remarkably increased by the combined use of rhodium salt, platinum salt and the Dye 1, and the safety to the safety light is not so poor. It is also seen that, in the emulsion whose grain size was made big to obtain about the same sensitivity, the safety thereof under the safety light deteriorated.
EXAMPLE 2
A silver chlorobromide emulsion (containing 50 mol percent of AgCl and 50 mol percent of AgBr) of about 0.6 micron mean grain size, not containing the metal compounds of the present invention [control emulsion (II)], was prepared in the presence of 10 - 1 mol of ammonia per 1 mol of silver halide, and an emulsion having substantially the same sensitivity as said control emulsion (II) was prepared with the same prescription but with further adding 6 × 10 - 8 mol of potassium hexachloroiridate (IV) and 3 × 10 - 7 mol of ammonium hexachlororhodate (III) per 1 mol of silver halide upon forming silver halide precipitates, and further adding 3 × 10 - 6 mol of potassium chloroaurate thereto upon post-ripening.
In the same way as in Example 1, 2 × 10 - 3 mol of the heretofore set out Dye 2 per 1 mol of silver halide was added thereto, then a stabilizer, a hardener, a coating assistant, etc., were added and the emulsion coated on a PET film.
On the other hand, a silver halide emulsion with a 1 micron mean grain size containing said metal compounds but free from the dye, prepared in the presence of 2.0 × 10 - 1 mol of ammonia per 1 mol of silver halide (control emulsion (II')), was similarly coated onto a PET film. The sensitivity and the fog under a No. 2A Safe Light were measured in the same manner as in Example 1.
TABLE 2 ______________________________________ Sensitivity exposed for 1/100 sec. Sensitivity exposed for 1/1,000,000 sec. Fog when exposed to No. 2A Safe Light (20W/m) for: 1 min. 20 min. ______________________________________ Control emulsion (II) 100 100 0 0.01 Control emulsion (II) + the group VIII metal 100 105 0 0.01 Control emulsion (II) + Dye 2 150 115 0 0.03 Control emulsion (II) + the group VIII metal + Dye 2 130 170 0 0.01 Control emulsion (II') 170 160 0.01 1.2 ______________________________________
As is obvious from Table 2, a remarkable sensitizing effect to flashlight exposure was recognized by the combined use of the group VIII metal salts and Dye 2 without deteriorating safety under a safety light, whereas emulsion (II') showed badly deteriorated safety under the safety light.
Example 3
An emulsion was prepared according to the procedure described in Example 2 using the Dye 3 instead of Dye 2, and tested in the manner described in Example 1. By the combined use of the group VIII metal salts and the Dye 3, a similar synergistic effect was recognized.
Example 4
To a silver chlorobromide emulsion (containing 50 mol % of AgBr) of about 0.5 micron mean grain size, not containing the group VIII metal compounds [control emulsion (III) ], prepared by the standard neutral process, and to an emulsion prepared with the same prescription but with adding 1 × 10 - 5 mol of potassium hexacyanoferrate (III) per 1 mol of silver halide contained in the emulsion upon forming the silver halide grains, and 7 × 10 - 3 mol of the Dye 4 per 1 mol of silver halide in the same manner as in Example 1, there were added a stabilizer, a hardener and a coating assistant and the emulsions coated on PET films. The dye sensitization degree of the samples thus obtained was measured in the same manner as in Example 1 to obtain the following results:
TABLE 3 ______________________________________ Sensitivity when exposed for 1/100 second Sensitivity when exposed for 1/1,000,000 sec. ______________________________________ Control emulsion (III) 100 100 Control emulsion (III) + the group VIII metal 100 105 Control emulsion (III) + Dye 4 140 120 Control emulsion (III) + the group VIII metal + Dye 4 140 170 ______________________________________
As is obvious from Table 3, the sensitivity to flashlight exposure is remarkably raised by the combined use of the group VIII metal and Dye 4. Substantially no fog appeared on the samples of the present invention when left for 20 minutes under a No. 2A Safe Light (20W/m), while the sensitivity thereof was raised.
1. Field of the Invention
This invention relates to a silver halide photographic emulsion, more particularly to a silver halide photographic light-sensitive material having high sensitivity to blue light in "flashlight exposure," which term is defined in the following explanation.
2. Description of the Prior Art
With the advent of what has been called the information age, various systems for rapidly communicating information have been developed. For example, there are press facsimile systems for rapidly sending newspaper manuscripts to remote places, high speed photographic typesetting systems for rapid typesetting, cathode ray-tube display systems for indicating the information output of a computer in letters or in patterns, and the like.
In these instruments for rapidly communicating information, short-time exposure, less than 1/100,000 second, sometimes as short as about 1/1,000,000 second, is often employed. Recently, the light-sensitive materials for use with such instruments have been more and more in demand.
As light sources used in these instruments, there have been used combinations of light sources having high illuminance, such as a xenon arc lamp, and high speed shutters; xenon flash light sources; and cathode ray-tube light sources. Amount these, cathode ray-tubes, especially those having fluorescent substance with short-time afterglow, are generally used for flying spot. For example, various fluorescent substances referred to as "P-15," "P-11," "P-16," "P-24 ," etc., are used, all of which are well known to one of ordinary skill in the art, Among these, P-15, P-11, P-16, and P-24 are known to have their maximum spectral energy distribution of emission at 505 nm, 460 nm, 385 nm and 520 nm, respectively. It is necessary in a light-sensitive material for recording images formed on a cathode ray-tube wherein these various kinds of fluorescent substances are used to have a high sensitivity in at least the blue light-sensitive region, especially at the wavelengths of from 380 to 520 nm.
The afterglow time of the emission of the aforesaid cathode ray-tube is usually as short as 1/10,000,000 to 1/100,000 second. Xenon flash lamps having an emission time similarly short are frequently used. In the present specification, the above-mentioned short-time exposure by a light source of this kind is generically referred to as "flashlight exposure."
The room wherein such light-sensitive materials are used is generally comparatively bright so that the operation can be conducted with ease. These materials are often used under comparatively bright yellowish-green safety light such as a Fuji Safe Light No. 2A (the percent transmission curve thereof is given in the drawing), and hence light-sensitive materials having a low sensitivity to safety lights of this kind are desirable.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a silver halide light-sensitive material having a high sensitivity to blue light in flashlight exposure.
Another object of the present invention is to provide a light-sensitive material having high sensitivity to blue light which is capable of being dealt with under bright yellowish-green safety light.
The blue-light-sensitive region (mainly the wavelength region of from 380 to 520 nm) corresponds to the light-sensitive region intrinsic to silver halide. In order to obtain a silver halide emulsion having high intrinsic sensitivity in flashlight exposure, processes for increasing the sensitivity by making the grain size of the silver halide large, processes for increasing the sensitivity by chemical sensitization, etc., were investigated. However, in the process comprising making the grain size large, the granular properties and the sharpness of the image formed were greatly deteriorated. In the process of chemical sensitization, the stability thereof to the safety light was deteriorated. In addition, when the sensitivity of the silver halide was increased by chemical sensitization in flashlight exposure, the storage stability thereof was deteriorated and, for example, undesirable fogs or stains were observed.
The objects of the present invention were attained by using a silver halide emulsion containing light-sensitive silver halide grains whose mean grain size by diameter (and by number) is equal to or smaller than 0.9 micron; at least one compound containing a group VIII metal in the periodic table in an amount of 10 - 6 to 10 - 3 mol per 1 gram mol of the silver halide; and at least one sensitizing dye represented by the general formula: ##SPC2##
wherein R and R 1 each represents a hydrogen atom, an alkyl group, a substituted alkyl group or an aryl group, Y represents an oxygen atom or N--R o (R o being a hydrogen atom, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group or an allyl group), L 1 and L 2 each represents a methine group and Z represents the non-metallic atoms necessary to complete a series of oxazoline nuclei; in a binder such as gelatin.
BRIEF DESCRIPTION OF THE DRAWING
The drawing is the percent transmission curve of a bright yellowish-green safety light.
DETAILED DESCRIPTION OF THE INVENTION
To explain more particularly about the general formula above R and R 1 each represents a hydrogen atom, an alkyl group i.e., unsubstituted alkyl group and substituted alkyl group usually used for sensitizing dyes) such as methyl, ethyl, n-propyl, etc., hydroxy alkyl (e.g., 2-hydroxyethyl, 4-hydroxybutyl), acetoxy alkyl (e.g., 2-acetoxyethyl, 3-acetoxypropyl), alkoxy alkyl (e.g., 2-methoxyethyl), carboxy groups containing alkyl (e.g., carboxymethyl, 2-carboxyethyl, 3-carboxypropyl, 2-(2-carboxyethoxy) ethyl), sulfo group containing alkyl (e.g., 2-sulfoethyl, 3-sulfopropyl, 4-sulfobutyl, 2-hydroxy-1-sulfopropyl, 2-(3-sulfopropoxy)ethyl, 2-acetoxy-1-sulfopropyl, 3-methoxy-2-(3-sulfopropoxy)propyl, 2-[2-(3-sulfopropoxy) ethoxy]ethyl, 2-hydroxy-3--(3'-sulfopropoxy) propyl), aralkyl (e.g., benzyl, phenethyl, p-sulfobenzyl, p-carboxybenzyl), allyl group, etc., or an aryl group such as phenyl, preferred carbon atom range of said alkyl moiety being up to 8; Y represents an oxygen atom or N--R o (wherein R o represents a hydrogen atom, the same alkyl group as R and R 1 , an aryl group (i.e. unsubstituted aryl group and substituted aryl group) such as phenyl, tolyl, naphthyl, etc., alkoxy phenyl (e.g., methoxyphenyl), halogenophenyl (e.g., chlorophenyl), etc.), L 1 and L 2 each represents a methine group preferably having up to 8 carbon atoms such as =CH--, =C(CH 3 )--, =C(C 2 H 5 )--, =C(C 6 H 5 )--, etc., and Z represents the non-metallic atoms necessary to complete a series of oxazoline nuclei such as the oxazoline nucleus, 4- and/or 5- alkyl substituted oxazoline nucleus (e.g., 4,4-dimethyloxazoline nucleus, 5-methyloxazoline nucleus, etc.), 4- and/or 5-phenyl substituted oxazoline nucleus (e.g., 4,5-diphenyloxazoline nucleus).
The sensitizing dyes used in the present invention are known and are described, for example, in British Pat. No. 1,074,433, and can be readily synthesized by reference to said specification.
Examples of dyes represented by the general formula are set out below, but the dyes used in the present invention are not to be thereby limited. ##SPC3##
(A mean grain size by diameter is designed hereinafter simply as "a mean grain size").
As a support in the present invention, there can be used glass, metal plates, wooden plates, baryta paper, cellulose derivative films, films of synthetic resins, synthetic papers, polyolefin-coated papers, and the like.
As a binder, water-soluble film-forming high molecular weight materials such as gelatin, polyvinyl alcohol, polyvinyl pyrrolidone, sodium alginate, carboxymethyl cellulose, etc., can be used separately or in combination. As the light-sensitive silver halide, there can be used silver chloride, silver bromide, silver chlorobromide, silver bromoiodide, etc. The grain size of the silver halide is, more effectively, smaller than 0.8 micron, most especially not larger than 0.6 micron, on the average.
The production of the light-sensitive silver halide grain, that is, the production of the silver halide emulsion, comprising forming the crystals of silver halide grains in a dispersed state in the binder, and developing the crystals into a suitable grain size, is conducted according to conventional methods.
The group VIII metals of the periodic table include iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum and, as the compounds containing these metals which are most preferably used in the present invention, there are iron, iridium and rhodium compounds. As examples of the group VIII metal compounds according to this invention, there are ferrous sulfate FeSO 4 . 5H 2 0; ferric chloride FeCl 3 ; potassium hexacyanoferrate (II) K 4 Fe(CN) 6 . 3H 2 O; potassium hexacyanoferrate (III) K 3 Fe(CN) 6 : cobaltous chloride CoCl 2 ; cobaltous nitrate Co(NO 3 ) 2 . 6H 2 O; potassium hexacyanocobaltate (III) K 3 Co(CN) 6 ; nickelous chloride NiCl 2 . 6H 2 O; nickel (II) nitrate Ni(NO 3 ) 2 . 6H 2 O; ruthenium (III) chloride RuCl 3 ; potassium hexachlororuthenate (IV) K 2 RuCl 6 ; rhodium (III) chloride RhCl 3 . 4H 2 O; ammonium hexachlororhodate (III) (NH 3 ) 3 RhCl 6 ; palladium (II) chloride PdCl 2 ; palladium (II) nitrate Pd(NO 3 ) 2 ; palladium (II) bromide PdBr 2 ; potassium hexachloropalladate (IV) K 2 PdCl 6 ; potassium tetrathiocyanatopalladate (II) K 2 Pd(CNS) 4 ; osmium (II) chloride OsCl 2 ; iridium (III) chloride IrCl 3 ; iridium (IV) chloride IrCl 4 ; iridium (III) bromide IrBr 3 . 4H 2 O; iridium (IV) bromide IrBr 4 ; potassium hexachloroiridate (III) K 3 IrCl 6 ; potassium hexachloroiridate (IV) K 2 IrCl 6 ; ammonium hexachloroplatinate (IV) (NH 4 ) 2 PtCl 6 ; potassium hexachloroplatinate (IV) K 2 PtCl 6 ; ammonium hexabromoplatinate (IV) (NH 4 ) 2 PtBr 6 ; and the like. These group VIII metal compounds are used in an amount of 10 - 6 mol to 10 - 3 mol per 1 mol of silver halide, independently or in combinations of more than one of these compounds. A gold compound can be preferably added to the emulsion in combination with any of those compounds of the group VIII metal. The addition of these compounds is properly conducted at the formation of the silver halide grains, at the start of the ripening of the emulsion or in the course thereof in the production of the silver halide emulsion. Otherwise, they may be added, before coating the ripened emulsion on a support, to the emulsion together with a known stabilizer such as 2-mercaptobenzimidazole, 1-phenyl-5-mercaptotetrazole, 5-methyl7-hydroxy-1,3,4-triazoindolizene, etc., antifogging agents, toning agents, coating assistants such as sodium alkylbenzenesulfonate, saponin, etc., plasticizers, hardeners such as formaldehyde, mucochloric acid, delustering agents, development accelerators, fluorescent brightening agents, color couplers or developing agents for activator development, etc. These materials are added, when desired, for their art-recognized function.
The sensitizing dyes used in the present invention are used in an amount of 10 - 5 to 10 - 2 mol per mol of silver halide contained in the silver halide emulsion, either separately or in combinations of more than one of them. The addition of the sensitizing dyes to the emulsion is carried out in the same manner as the aforesaid metal compounds. They may be added to the emulsion simultaneously with the said metal compounds, or may be added independently regardless of the order.
After the flashlight exposure, the light-sensitive material prepared in this way can be developed and fixed in the conventional manner, or may be treated in the manner generally known as the diffusion transfer process, or may be treated according to the developing process known as activator development (a process comprising developing a light-sensitive material containing a developing agent with a solution containing alkaline material without developing agent) by previously adding a sufficient amount of a developing agent to the light-sensitive layer.
It has been known that, regardless of the existence of the above-mentioned metal compounds, the sensitizing dyes represented by the general formula are capable of spectrally sensitizing light-sensitive materials. As the result of various experiments in flashlight exposure, the sensitizing effect of the emulsion not containing above-mentioned metal compounds is small while in the usual exposure, the emulsion not containing said metal compounds shows at least about the same sensitizing effect as that of the emulsion containing said metal compounds. However, surprisingly, in the emulsion containing the group VIII metal compounds of the present invention, a remarkable sensitizing effect is produced as is shown in the following examples. On the other hand, the light-sensitive material whose sensitivity in flashlight exposure is increased by chemical sensitization or by the process whereby the grain size is made larger, has an increased sensitivity to safety light, and under a safety light is deteriorated, as is shown in the following examples. Especially, the mean grain size of the silver halide is quite important for use under a safe light, and the mean grain size of the silver halide is advantageously not larger than 0.9 micron.
A bright safety light is desirable and it is the prerequisite for the light-sensitive material used in the present invention that it can be safely dealt with under a yellowish-green safety light, and hence it can of course be dealt with under red light, such as a Fuji Safe Light No. 2, or under the light passed through a safety light filter which transmits light of longer wavelengths.
It has long been known that, when added to a photographic emulsion, the above-mentioned metal compounds exhibit various effects. As is described in U.S. Pat. 2,448,060, when hexahalogenoruthenate (III), hexahalogenorhodate (IV), hexahalogenopalladate (IV), hexahalogenoosmate (IV), hexahalogenoiridate (IV), hexahalogenoplatinate (IV), etc., are added to a silver halide emulsion upon ripening, the intrinsic sensitivity of the light-sensitive material wherein this emulsion is used increases and, as is described in U.S. Pat. No. 2,566,245, when said compounds are added to a silver halide emulsion in large amounts, the storage stability of the light-sensitive material obtained under the circumstances of high temperature and high humidity is improved. Furthermore, it is described that potassium hexacyanocobaltate (III) (see U.S. Pat. No. 2,517,541) or rhodium trichloride (see FIAT report No. 360) are capable of making the resulting light-sensitive material high-contrast (i.e. high gamma value) when added to a silver halide emulsion.
The group VIII metal compounds used in the present invention are added only for the object of the present invention; however, the above-mentioned various photographic effects may be obtained at the same time. In addition, as described in British Pat. No. 570,393, a process comprising adding a gold compound upon ripening to raise the intrinsic sensitivity of the light-sensitive material can also be applied.
The present invention will now be further illustrated in more detail by the following examples.
EXAMPLE 1
A silver bromoiodide emulsion (containing 2 mol percent of AgI) of about 0.6 micron mean grain size, not containing the compounds of a group VIII metal (hereinafter referred to merely as a "metal compound" in the examples) [control emulsion (I) ], was prepared in the presence of 1 × 10 - 1 mol of ammonia per 1 mol of silver halide, and an emulsion having about the same sensitivity as that of the control emulsion (I) was prepared with the same prescription with adding 3 × 10 - 6 mol of ammonium hexachlororhodate (III) per 1 mol of silver halide contained in the said emulsion upon forming the silver halide grains and further adding 2 × 10 - 5 mol of potassium chloroplatinate per 1 mol of silver halide upon post-ripening. Each of these two emulsions was divided into two portions, then 6 × 10 -3 mol of the Dye 1 per 1 mol of silver halide contained in the emulsion was added to one portion, leaving the other portion as such. In addition, 2-mercaptobenzimidazole was added thereto as a stabilizer, mucochloric acid as a hardener, and saponin as a coating assistant, and the emulsion was then coated on a polyethylene terephthalate (PET) film.
On the other hand, 8 × 10 - 1 mol of ammonia per 1 mol of silver halide was added upon precipitating the silver halide to prepare an emulsion of 0.95 micron mean grain size (containing the above-mentioned metal compound, but free from the dye), and the emulsion coated on a PET film base (which corresponds to control emulsion (I')).
The above-described samples were imagewise exposed for 1/100 and 1/1,000,000 second using a Mark III sensitometer made by EG G Co. in the U.S.A. The exposed samples were developed with the following developer for 3 minutes at 20° C.
______________________________________ Metol 8 g Sodium Carbonate (monohydrate) 150 g Hydroquinone 30 g Potassium Bromide 7 g Water to make up 1 liter ______________________________________
After fixing, washing and drying, the transmission density was measured. The sensitivity value was determined as the reciprocal of the quantity of light which gave a density of 2.5. The sensitivity of the control emulsion (I) was calculated as 100, and the relative sensitivities of the other emulsions based on that of the control emulsion (I) are given in Table 1.
In addition, the fog density value obtained by leaving the samples under a Fuji No. 2A Safe Light (20W) at a distance of 1 m for 1 minute and 20 minutes, and then developing them with the above-described developer, was also measured.
TABLE 1 ______________________________________ Sensitivity exposed for 1/100 sec. Sensitivity exposed for 1/1,000,000 sec. Fog when exposed to No. 2A Safe Light for: 1 min. 20 min. ______________________________________ Control emulsion (I) 100 100 0.0 0.03 Control emulsion (I) + the group VIII metal 98 100 0.0 0.02 Control emulsion (I) + Dye 1 130 110 0.0 0.04 Control emulsion (I) + the group VIII metal + Dye 1 120 150 0.0 0.01 Control emulsion (I') 150 150 0.01 1.00 ______________________________________
As is obvious from Table 1, the sensitivity of the emulsion to flashlight is remarkably increased by the combined use of rhodium salt, platinum salt and the Dye 1, and the safety to the safety light is not so poor. It is also seen that, in the emulsion whose grain size was made big to obtain about the same sensitivity, the safety thereof under the safety light deteriorated.
EXAMPLE 2
A silver chlorobromide emulsion (containing 50 mol percent of AgCl and 50 mol percent of AgBr) of about 0.6 micron mean grain size, not containing the metal compounds of the present invention [control emulsion (II)], was prepared in the presence of 10 - 1 mol of ammonia per 1 mol of silver halide, and an emulsion having substantially the same sensitivity as said control emulsion (II) was prepared with the same prescription but with further adding 6 × 10 - 8 mol of potassium hexachloroiridate (IV) and 3 × 10 - 7 mol of ammonium hexachlororhodate (III) per 1 mol of silver halide upon forming silver halide precipitates, and further adding 3 × 10 - 6 mol of potassium chloroaurate thereto upon post-ripening.
In the same way as in Example 1, 2 × 10 - 3 mol of the heretofore set out Dye 2 per 1 mol of silver halide was added thereto, then a stabilizer, a hardener, a coating assistant, etc., were added and the emulsion coated on a PET film.
On the other hand, a silver halide emulsion with a 1 micron mean grain size containing said metal compounds but free from the dye, prepared in the presence of 2.0 × 10 - 1 mol of ammonia per 1 mol of silver halide (control emulsion (II')), was similarly coated onto a PET film. The sensitivity and the fog under a No. 2A Safe Light were measured in the same manner as in Example 1.
TABLE 2 ______________________________________ Sensitivity exposed for 1/100 sec. Sensitivity exposed for 1/1,000,000 sec. Fog when exposed to No. 2A Safe Light (20W/m) for: 1 min. 20 min. ______________________________________ Control emulsion (II) 100 100 0 0.01 Control emulsion (II) + the group VIII metal 100 105 0 0.01 Control emulsion (II) + Dye 2 150 115 0 0.03 Control emulsion (II) + the group VIII metal + Dye 2 130 170 0 0.01 Control emulsion (II') 170 160 0.01 1.2 ______________________________________
As is obvious from Table 2, a remarkable sensitizing effect to flashlight exposure was recognized by the combined use of the group VIII metal salts and Dye 2 without deteriorating safety under a safety light, whereas emulsion (II') showed badly deteriorated safety under the safety light.
Example 3
An emulsion was prepared according to the procedure described in Example 2 using the Dye 3 instead of Dye 2, and tested in the manner described in Example 1. By the combined use of the group VIII metal salts and the Dye 3, a similar synergistic effect was recognized.
Example 4
To a silver chlorobromide emulsion (containing 50 mol % of AgBr) of about 0.5 micron mean grain size, not containing the group VIII metal compounds [control emulsion (III) ], prepared by the standard neutral process, and to an emulsion prepared with the same prescription but with adding 1 × 10 - 5 mol of potassium hexacyanoferrate (III) per 1 mol of silver halide contained in the emulsion upon forming the silver halide grains, and 7 × 10 - 3 mol of the Dye 4 per 1 mol of silver halide in the same manner as in Example 1, there were added a stabilizer, a hardener and a coating assistant and the emulsions coated on PET films. The dye sensitization degree of the samples thus obtained was measured in the same manner as in Example 1 to obtain the following results:
TABLE 3 ______________________________________ Sensitivity when exposed for 1/100 second Sensitivity when exposed for 1/1,000,000 sec. ______________________________________ Control emulsion (III) 100 100 Control emulsion (III) + the group VIII metal 100 105 Control emulsion (III) + Dye 4 140 120 Control emulsion (III) + the group VIII metal + Dye 4 140 170 ______________________________________
As is obvious from Table 3, the sensitivity to flashlight exposure is remarkably raised by the combined use of the group VIII metal and Dye 4. Substantially no fog appeared on the samples of the present invention when left for 20 minutes under a No. 2A Safe Light (20W/m), while the sensitivity thereof was raised.