JPH04251842A - Method for directly forming output image of positive computer - Google Patents

Abstract

PURPOSE: To provide a method to form a computer output image having enhanced density and gradation by using a direct positive silver halide photosensitive material. CONSTITUTION: A photographic material consisting of a supporting body and silver halide particles which are not fogged and produce an inner latent image is exposed to light in 440 to 480nm wavelength region with at least 0.1mJ/m<2> intensity for 10<-5> to 10<-8> sec. Then (a) the material exposed for an image is developed with a surface developer in the presence of a developing nuclei forming agent, or (b) the exposed material for an image is subjected to flashing all over to fog the material before the developing process with a surface developer. Thus, the photosensitive material shows the enhanced max. density and gradation to form a direct positive computer output image. In this method, the photographic emulsion layer contains at least one kind of merocyanine dye.

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION This invention relates to a method of forming direct-positive computer output images with enhanced maximum density and gradation and to photographically sensitive direct-positive silver halide emulsion materials used in accordance with this method.

0002

[Prior Art] In silver halide photography, a photographic method in which a positive image is created without using a negative image or an intermediate process for producing a negative image is called a direct positive method. Photographic light-sensitive materials and photographic emulsions are called direct-positive materials and direct-positive emulsions, respectively.

Two main methods are known for producing direct positive images. According to a first type of method, a prefogged silver halide is exposed and developed in the presence of a desensitizer. Such a method is used, for example, in the US-A
3364026, 3501305 and GB-A707
704 has been described. According to the second type of method,
A silver halide emulsion (generally called an internal latent image type silver halide emulsion) containing silver halide mainly having photosensitive fine grains inside the grains is exposed imagewise, and the exposed emulsion is exposed to light in the presence of a development nucleation agent. A photoflash is performed over the entire surface to provide fogging before the underlying or exposed emulsion is surface developed.

The present invention relates to a second type of process and to photographic materials containing silver halide grains having primarily light-sensitive fine grains inside the grains. A method for producing a direct positive image by developing an exposed internal latent image-type silver halide emulsion with a surface developer in the presence of a development nucleating agent, and the photographic light-sensitive materials used in such a method are particularly described. G.B.
-A1011062, 1151363, 1195837
, Special Publication No. 43-29405 (1968) and US-A
2456953, 2497875, 2497876, 2
588982, 2592250, 2675318, 32
27552, 3761276 and 4540655.

The present invention relates to direct positive silver halide materials containing unfogged silver halide emulsions.

[0006]Due to their practical and economic utility in the field of computer information output, the use of direct-positive materials and direct-positive emulsions has recently been chosen.

A conventional desensitized direct positive silver halide emulsion for recording computer information at 460 nm gives a direct positive image with a maximum density of about 1.4 and a tone of only 1.22. However, images with such low maximum densities have poor reading quality and the gradations are insufficient to obtain high quality images.

Imagewise exposing a silver halide photographic emulsion layer containing unfogged internal latent image type silver halide grains to a cyanine dye or carbocyanine having a longest wavelength absorption maximum on the silver halide not exceeding 590 nm. It is known from EP-A 331 185 to form positive images directly by developing exposed emulsion layers containing dyes.

Although the maximum density and gradation are slightly improved by this method, they remain substantially unsatisfactory.

[0010] A simple unfogged silver halide emulsion containing a methine or polymethine spectral sensitizer and in which the silver halide grains of the emulsion layer have no chemically induced internal or surface sensitivity. 1×10-12
At least 0.01 at an intensity of Watts/cm2
imagewise exposing for 2 seconds and then developing the imagewise exposed emulsion layer chemically in the presence of a fogging agent or performing a light flashing to fog the imagewise exposed emulsion layer. It is also known from US Pat. No. 3,736,140 to produce positive silver images.

However, short exposure times such as those normally used in COM recorders, ie 10
-5 to 10-8 seconds, the speed and gradation of the photographic material can be inferior to that obtained at longer exposure times, as described by T. H. It is known from the 4th edition of "The Theory of the Photographic Process" by James. This phenomenon is applied to direct positives containing internally latent image silver halide emulsions that have not been externally fogged or have not been ripened but have been fogged by full post-exposure or development in the presence of a development nucleating agent. It also occurs in photographic materials. Shortening the development time only exacerbates this phenomenon.

0012

It is therefore an object of the invention to provide direct positive computer output (C) with enhanced density and gradation.
It is an object of the present invention to provide a method for forming an OM) image.

It is another object of the invention to provide a photographically sensitive direct positive silver halide emulsion material for use in accordance with this method.

Other objects of the invention will become apparent from the following description.

[0015]

According to the present invention, a photographic light-sensitive material comprising a support and at least one photographic emulsion layer containing unfogged internally latent image type silver halide grains is provided. 10-5 at high intensity of .1mJ/m2
imagewise exposing the imagewise exposed material to light in the wavelength range from about 440 to about 480 nm for a short time period of ~10-8 seconds; and (a) surface developing the imagewise exposed material in the presence of at least one development nucleating agent. or (b) an overall light flashing to fog the exposed material according to said image prior to its development with a surface developer. A method has now been discovered, characterized in that the photographic emulsion layer contains at least one merocyanine dye.

The present invention also provides a photographically sensitive direct positive material for producing direct positive images, said material comprising a support and at least one silver halide grain containing unfogged internally latent image type silver halide grains. The photographic emulsion layer is characterized in that it contains at least one kind of merocyanine dye.

A photographic light-sensitive material comprising a support, at least one photographic emulsion layer containing unfogged internally latent image type silver halide grains, and at least one merocyanine dye is heated to a concentration of at least 0.1 mJ/m2. 10- with high strength
imagewise exposing the imagewise exposed material to exposure light in the wavelength range from about 440 to about 480 nm, preferably at a wavelength of 460 nm, for a short time period of 5 to 10-8 seconds, and then (a) depositing the imagewise exposed material in a photographic emulsion layer, (b) a hydrophilic colloid layer in water-permeable relationship with the emulsion layer, or developed with a surface developer in the presence of at least one development nucleating agent contained in said surface developer; Substantially higher than the limited enhancement obtained using cyanine dyes by prior art methods, by blanket light flashing to fog the imagewise exposed material before its development in a developer. It has been unexpectedly discovered that maximum density and gradation enhancement can be obtained. Moreover, according to the present invention, no reduction in speed was observed at all. By adding at least one rhodacyanine dye in addition to the at least one merocyanine dye to the photographic emulsion, the maximum density and gradation could be further enhanced.

Merocyanine is a dye having a heterocycle containing a trivalent nitrogen atom, and the heterocycle is =(CH-CH
) n = formula (in this formula, n is 0, 1, 2,
It is attached to a ketomethylene structure, such as a rhodanine ring, a pyrazolin-5-one ring, a thiohydantoin ring, etc., through a carbon chain having an even number of carbon atoms according to 3-----).

Merocyanine and rhodacyanine dyes are not utilized as spectral sensitizers and may not have an absorption spectrum in the previously defined exposure wavelength range.

Examples of merocyanine dyes that can be suitably used according to the invention are the dyes listed in Table 1 below.

[0021]

[Table 1]

[Table 2]

[Table 3]

Rhodacyanine can be obtained, for example, by reaction of simple merocyanine with methyl halide or methyl sulfate, followed by condensation of the reactive methylthio group formed with other compounds having reactive methyl or methylene groups. It is a complex cyanine. Examples of rhodacyanine dyes that can be used in addition to merocyanine dyes are listed in Table 2 below.

[0023]

[Table 4]

[Table 5]

A detailed description of merocyanines and their preparation can be found in "Photochemistry" by P. Grafkits, Volume 2, pages 844 onwards, published by Fountain Press, London in 1960. Details regarding rhodacyanines, so-called complex merocyanines, and their preparation can also be found in the same document, from page 857 onwards.

The photographic emulsion contains a merocyanine dye and possibly an additional rhodacyanine dye in concentrations almost equivalent to those used in conventional silver halide negative emulsions. The merocyanine sensitizers or merocyanine and rhodacyanine sensitizers can be used in a wide range of concentrations from about 1.0 x 10-5 to about 3 x 10-3 moles per mole of silver halide, particularly about 4×10−
Preferably, a wide range of concentrations from 5 to 2.times.10@-3 molar is used.

To carry out the method of the invention, at least one development nucleating agent is included in the developer before development of the exposed photographic material or in the prebath supplied to the photographic material. However, it is preferred that at least one development nucleating agent is included in the silver halide emulsion layer or in a hydrophilic colloid layer in water-permeable relationship with this layer. The development nucleating agent for use in accordance with the present invention may be any compound known for this purpose. Suitable development nucleating agents are, for example, sulfur compounds such as thiourea dioxide, phosphonium salts such as phosphonium tetrahydroxymethyl chloride, hydroxylamine, bis-p-aminoethyl sulfide and water-soluble salts thereof, reductic acid and its derivatives, e.g. 4,
4,5,5-tetramethylreductinic acid, cosinic acid, ascorbic acid, 2-hydroxy-1,3-cyclohexanedione, 2-acetoxy-1,2-di(2-pyridyl)ethanone, 2-hydroxy -1,2-di(2-pyridyl)ethanone, reactive N-substituted cycloammonium quaternary
and hydrazine-type compounds such as 1-diphenyl-hydrazine hydrochloride and 1,2-dipridyl-hydrazine hydrochloride.

Suitable development nucleating agents of the type of reactive N-substituted cycloammonium quaternary salts correspond to general formula I below.

[0028]

[Chemical formula 1]

In this formula, R is hydrogen, an alkyl group,
Represents a substituted alkyl group, aralkyl group, substituted aralkyl group, alkaryl group, substituted alkaryl group, aryl group, or substituted aryl group, Z represents a heterocycle or an atom necessary to complete the substituted heterocycle, and this heterocycle The ring has a fused heterocycle or a carbon ring, and X is an anion.

A typical development nucleating agent corresponding to general formula I has the following structural formula.

[0031]

[Case 2]

Other suitable development nucleating agents for use in accordance with the present invention are hydrazine type compounds corresponding to the general formula II below:

R1 -NH-NH-CO-R2 (II
)

In this formula, R1 and R2 (which may be the same or different) each represent hydrogen, an alkyl group, a substituted alkyl group, an aryl group or a substituted aryl group.

Preferred development nucleating agents for use in accordance with the invention are phenyl hydrazides such as 1-formyl-2-phenyl-hydrazine, 1-p-acetamidophenyl-2-acetyl-hydrazine and 1-[2-
(2,4-di-tert-phenyl-phenoxy)-propionamidophenyl]-2-formylhydrazine.

Another class of suitable hydrazine-type development nucleating agents are heteronitrogen-containing rings or substituted heteronitrogen-containing rings, such as thiohydantoin rings or mercaptotetrazolyl rings. Such compounds are compound III below.
and IV.

[0037]

[Chemical formula 3]

[C4]

A preferred class of hydrazine-type development nucleating agents used in accordance with the present invention, containing a heteronitrogen-containing ring, is a pyrazolidin-3-one-1-yl-phenyl group or a substituted pyrazolidin-3-one. -yl-phenyl group-containing hydrazine. Examples of such preferred development nucleating agents are shown in Table 3 below.
It is a compound according to III.

[0039]

[Table 6]

[Table 7]

An interesting class of development nucleating agents corresponding to general formula II are phenyl hydrazides containing water-solubilized polyhydroxy moieties. A representative compound of this type corresponds to general formula XIV below.

[0041]

[C5]

In this formula, n is a positive integer ranging from 1 to 10, and R3 is hydrogen, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, a heterocyclic group, or a substituted heterocyclic group.

One suitable example of a heterocyclic group represented by R3 in general formula XIV is pyrazolidine-3-
It is an on-1-yl group and may be substituted.

Suitable examples of development nucleating agents corresponding to general formula XIV are compounds in which n is 4 or 5 and R3 is a hydrogen atom.

Mixtures of at least two of the development nucleating agents mentioned above can be advantageously used.

As mentioned above, a nucleating amount of a development nucleating agent is present during the development of the photographic material, and for this purpose, for example, a water-permeable agent is present in the light-sensitive silver halide emulsion layer or with the emulsion layer. It can be included in the associated hydrophilic colloid layer. Otherwise, the development nucleating agent can be added to the development bath or a separate bath.

When used in the silver halide emulsion layer, the development nucleating agent contains from 10@-4 to 10@-4 per mole of silver halide.
It is contained in a concentration of 10-1 molar.

Prior to coating the composition forming the photographic layer containing at least one development nucleating agent, the development nucleating agent can be dissolved in an organic solvent and added to said composition. For example, if 1.3 x 10-3 mol of development nucleating agent is N
- added in the form of a 3.5% solution per mole of silver in methylpyrrolidone.

According to one preferred embodiment, the development nucleating agent is added in dispersed form to the hydrophilic colloid composition forming the emulsion layer or the hydrophilic colloid layer.

When these hydrazines are contained in the hydrophilic colloid layer, preferably in dispersed form in the internal latent image type silver halide emulsion layer, the direct positive image obtained upon development has extremely fine grains.

The development nucleating agent is first dissolved in at least one water-immiscible oil solvent or oil former, and the resulting solution is added to an aqueous phase containing a hydrophilic colloid, preferably gelatin, and a dispersant. The mixture is then passed through a homogenizer to form a dispersion of the oily solution in the aqueous medium, and the dispersion is combined with a hydrophilic colloid composition,
For example, mixing silver halide with a gelatin emulsion and applying the resulting composition in conventional manner to produce a system in which particles of development nucleating agent surrounded by an oily film are distributed throughout the gel matrix. It can be contained in the hydrophilic colloid composition forming the emulsion layer or the hydrophilic colloid layer, depending on the method. Dissolution of the developer nucleating agent into the oil former is facilitated by the use of a low-boiling, water-immiscible co-solvent which is later removed by evaporation.

The development nucleating agent can be dispersed in the hydrophilic colloid composition with the aid of at least one known oil former, such as an alkyl ester of phthalic acid. These oil formers may vary in concentration over a wide range, such as from about 0.1 to about 10 parts by weight, preferably from about 0.5 to about 2 parts by weight, based on the amount of development nucleating agent dispersed together. Amounts ranging from parts by weight can be used.

It is useful to combine the oil former with at least one co-solvent which is insoluble or almost insoluble in water and has a boiling point not exceeding 150° C., for example an alkyl acetate such as ethyl acetate.

According to one preferred embodiment of the invention, the development nucleating agent is prepared by mixing the development nucleating agent without oil former and solvent with an aqueous hydrophilic colloid solution, preferably an aqueous gelatin solution, and mixing the resulting mixture. passing through a homogenization device and adding the resulting dispersion to the hydrophilic colloid composition forming the emulsion layer or the hydrophilic colloid layer;
By coating the hydrophilic colloid composition on a support, it is contained in the hydrophilic colloid composition that forms the silver halide emulsion layer or the hydrophilic colloid layer.

[0055] The homogenizing device may be any device currently used for preparing dispersions, such as an ultrasonic power generator, a milling machine such as a ball mill, a sand mill, a colloid mill, or the like.

In the photographic direct positive material according to the invention, the development nucleating agent is preferably contained in the internal latent image type silver halide emulsion layer. However, the development nucleating agent can also be contained in a hydrophilic colloid layer in water permeable relationship with the internal latent image type silver halide emulsion layer. Such a hydrophilic colloid layer may be any layer forming part of the photographic direct positive material according to the invention. This layer may be, for example, a photosensitive layer, an interlayer, a filter layer, a protective layer, an antihalation layer, an antistress layer, an auxiliary layer or any other layer. That is, it is impossible to prevent the development nucleating agent from diffusing into any internal latent image type silver halide emulsion layer to which it is applied.

The development nucleating agent used according to the invention is contained in the layer in an amount that provides a satisfactory maximum density value, such as at least 1.50, when the internal latent image emulsion is developed by a surface developer solution. It is preferable. This amount varies within wide limits and is determined by the nature of the silver halide emulsion, the chemical structure of the development nucleating agent, and the development conditions. However, amounts of from about 0.1 to about 15 grams per mole of silver halide in internal latent image type silver halide emulsions are generally effective;
．． More preferred is an amount of 6 to about 9g. When the development nucleating agent is contained in a hydrophilic colloid layer that is in water-permeable relationship with the internal latent image type silver halide emulsion layer, it may be It is appropriate to include the development nucleating agent in the amounts mentioned above.

An internal latent image type silver halide emulsion is an emulsion in which the maximum density obtained when developed with an internal type developer exceeds the maximum density obtained when developed with a surface type developer. Internal latent image emulsions suitable for use in accordance with the present invention are such that these emulsions are coated on a transparent support and
When exposed for a period of 100 to 1 second and then developed for 3 minutes at 20°C in an internal developer solution as described below, a silver halide emulsion exposed as described above produces the surfaces described below. Provides a maximum density that is at least 5 times higher than the maximum density obtained when developed for 4 minutes at 20° C. in a mold developer solution.

Internal type developer A hydroquinone

15g Monomethyl-p-aminophenol sulfate 15g Anhydrous sodium sulfite
50g potassium bromide
10g
Sodium hydroxide
2
5g crystalline sodium thiosulfate
20
g Water required to make 1 liter in total

Surface type developer B p-hydroxyphenylglycine
10g crystalline sodium carbonate
100g Water required to make 1l in total

Internal latent image type silver halide emulsions which can be used according to the invention are for example US-A259225
0, 3206313, 327157, 3447927,
3511662, 3737313, 3761276, G
B-A1027146 and Special Publication No. 52-34213 (
1977). However, the silver halide emulsions used in the present invention are not limited to those described in these documents.

Internal latent image type silver halide emulsions suitable for use in the process of the invention include, for example, US-A37
61276 and 3850637, not externally capped or only minimally capped, and not chemically aged or only minimally aged. It is an emulsion.

Photographic emulsions are described, for example, in P. Graphkits, Focal Press, London 1
G. in "Photographic Emulsion Chemistry" published in 1966. F. Dufuin and London, Focal Press, 1966.
V. in “Preparation and Coating of Photographic Emulsions”, published in 2010. L
．． It can be prepared by various methods described by Zerkiman et al.

The silver halide photographic emulsions used in the method of the present invention are prepared by mixing the halide solution and the silver solution under conditions that partially or fully control temperature, concentration, order of addition, and rate of addition. It can be prepared by: Silver halide can be precipitated by a single jet method, a double jet method or a conversion method. The conversion method has proven to be particularly suitable. According to this method, silver halide with relatively high solubility is converted into silver halide with relatively low solubility. For example, a silver chloride emulsion may be used in the presence of water-soluble bromide and optionally iodide, the amount of which is selected with respect to the final composition required, as a silver chloride bromide iodide emulsion or a silver bromide iodide emulsion. is converted to This conversion is preferably carried out very slowly in several successive steps, converting a portion of the more soluble silver halide at once. Another technique that can prepare emulsions with enhanced internal latent image sensitivity is GB-A10110
62.

The silver halide grains of the photographic emulsions used in the process of this invention have a regular crystalline morphology, such as a cubic or octahedral morphology, or have a transitional morphology. These particles may have an irregular morphology, such as a spherical or tubular morphology, or they may have a complex crystalline morphology consisting of a mixture of the aforementioned regular and irregular crystalline morphologies.

The silver halide grains may have a multilayer grain structure.

According to one simple embodiment of the particles, they contain cores and shells with different halide compositions and/or with different modifications, such as doping. In addition to having differently configured cores and shells, the silver halide grains may also contain intermediate different phases.

To produce the photographic emulsions used in the method of the invention, at least two differently prepared
Different types of silver halide emulsions can be mixed.

[0069] The average grain size of the silver halide grains is 0.1 to
It is in the range of 2.0 μm, preferably in the range of 0.3 to 0.8 μm.

The grain size distribution of the silver halide grains in the photographic emulsion used in the method of the invention can be either uniform or non-uniform. A uniform particle size distribution is obtained when 95% of the particles have a particle size that deviates no more than 30% from the average particle size.

In addition to silver halides, the emulsions may also contain organic silver salts such as silver benzotriazolate and silver behenate.

Silver halide crystals include Rh3+, Ir4+,
It can be doped with Cd2+, Zn2+, Pb2+.

Photographic emulsions contain substances (
(in addition to any ions provided by the light-sensitive emulsion itself). Such compounds and methods of using these compounds are described in GB-A119583
It is listed in 7.

The emulsion can be left unwashed or can be desalted by conventional methods such as dialysis, flocculation and redispersion, or ultrafiltration.

Typically, the light-sensitive silver halide emulsions used in the process of this invention have not been chemically sensitized. However, these emulsions may be slightly chemically sensitized or prefogged. Chemical sensitization is described, for example, in the above-mentioned "Chemistry and Physics of Photography" by P. Grafkitz, the above-mentioned "Photographic Emulsion Chemistry" by G. F. Dufuin, and the above-mentioned "Preparation of Photographic Emulsions" by V.L. and coating” and
Edited by Frieser and published by Academic Publishing Association 19
It can be carried out as described in "Fundamentals of Photographic Processes Using Silver Halides" published in 1968.

Density-enhancing compounds may be included in the hydrophilic colloid layer in water-permeable relationship with the internal latent image type silver halide emulsion layer, but these compounds may be incorporated into the photographically sensitive direct positive silver halide layer. material, preferably in its internal latent image type silver halide emulsion layer. Suitable concentration-enhancing compounds are formic acid, oxalic acid, glyoxyacid or salts thereof and polyethylene glycols. When included in a photographic material, the concentration-enhancing compound may be between 4 and 600 mg/m
2, preferably 40 to 300 mg/m2. When the concentration-enhancing compound is included in the hydrophilic colloid layer, it is present in the form of a salt, such as a sodium or potassium formate or oxalate.

It is also possible to incorporate the concentration-enhancing compound into a hydrophilic colloid layer which is not in direct water permeable relationship with the internal latent image type silver halide emulsion layer, for example when the non-permeable support is This is because a barrier is formed between the layer and the hydrophilic colloid layer. In this case, during processing of the exposed material with a developer or prebath, the concentration-enhancing compound diffuses via said developer or prebath into the silver halide emulsion layer and takes effect there. . Such a layer is, for example, a layer applied to the back side of the support and serving another purpose. Examples of such layers include, for example, back layers, anti-curl layers, and antistatic layers.

The density-enhancing compound is also present in the developer at a concentration of 0.2 to 3
It may be added in an amount of 0 g/l, preferably in an amount of 1 to 10 g/l. Concentration-enhancing compounds may be added to other processing solutions, such as prebaths. When the density-enhancing compound is added to the developer solution or prebath, it is present in acid or salt form.

One preferred concentration-enhancing compound is oxalic acid because it has the highest concentration-enhancing effect and can therefore be used at relatively low concentrations.

Any known method can be used to process the photographic material according to the method of the invention. In particular, the processing method utilized by the present invention essentially includes a development step and a fixing step. Stopping and washing steps can also be included if necessary. The treatment temperature is usually selected within the range of 18°C to 50°C. However, temperatures below 18°C and temperatures above 50°C can also be used if necessary. The treatment time can be varied within a wide range, provided that the mechanical strength of the material being treated is not adversely affected and no decomposition occurs.

The hydroquinone type developer used for developing photographic materials exposed according to the invention contains at least one alkanolamine selected from primary, secondary and tertiary alkanolamines. ing. Suitable alkanolamines include, for example, N, N, N
-triethanolamine, 2-amino-2-hydroxymethylpropane-1,3-diol, N-methyldiethanolamine, N-ethyldiethanolamine, diisopropanolamine, N,N-diethanolamine, 3
, 3'-aminodipropanol, 2-amino-2-methylpropane-1,3-diol, N-propyldiethanolamine, N-butyldiethanolamine, N,N-
Dimethylethanolamine, N,N-diethylethanolamine, N,N-diethylisopropanolamine,
1-aminopropan-2-ol, N-ethanolamine, N-methylethanolamine, N-ethylethanolamine, N-ethylpropanolamine, 3-aminopropanol, 3-dimethylaminopropanol, 4-
There are aminobutanol and 5-aminopentan-1-ol.

The alkanolamine or mixture of alkanolamines can be present in the developer solution in an amount of 1 to 100 g/l, preferably 10 to 60 g/l.

In the developer used in the method of the present invention, hydroquinone alone or hydroquinone and 1-
A combination of a phenyl-3-pyrazolidinone compound and a second developer of the type p-N-methylaminophenol can be used as a developer. Specific examples of hydroquinones include hydroquinone, methylhydroquinone, t-butylhydroquinone.

Particularly useful 1-phenyl-3-pyrazolidinone developers that can be used in combination with hydroquinone are 1-phenyl-3-pyrazolidinone, 1-phenyl-4-methyl-3-pyrazolidinone, 1-phenyl-3-pyrazolidinone, and 1-phenyl-3-pyrazolidinone.
4-ethyl-5-methyl-3-pyrazolidinone and 1
-phenyl-4,4'-dimethyl-3-pyrazolidinone.

N-methyl-p-aminopheninol and 2
, 4-diaminophenol can be used in combination with hydroquinone as a developer.

[0086] The second method used in the treatment method of the present invention
When the developer is one of the types of 1-phenyl-3-pyrazolidinone compounds, this developer has a concentration of 2 to 20 g/
Preferably, it is contained in an amount of 1.

The developer solution contains a preservative such as a sulphite, for example sodium sulphite, in an amount ranging from 45 to 160 g/l.

The developer may contain alkali-imparting substances such as sodium and potassium hydroxides, alkali metal salts of phosphoric acid and/or silicic acid, such as trisodium phosphate, sodium or potassium oil silicates, metasilicates, hydroxides, etc. Contains disilicate, and sodium carbonate. The alkali-providing substance can be partially or completely replaced with an alkanolamine.

The developer solution may contain buffering agents such as carbonates, such as sodium carbonate, potassium carbonate, trisodium phosphate and sodium metaborate.

To reduce the formation of fog (Dmin), the developer may further contain inorganic antifoggants such as bromides, for example potassium bromide and/or organic antifoggants such as benzimidazole, for example 5-nitrobenzene. Benzotriazoles such as imidazole, benzotriazole itself, and 5-methylbenzotriazole may also be included.

The developer contains, for example, a toning agent, a development accelerator, an oxidation preservative, a surfactant, an antifoaming agent, a water softener, an anti-sludge agent, a curing agent including a latent curing agent, and a viscosity modifier. It may contain other ingredients.

It is of course possible to regenerate the developer using known methods.

Although often not necessary, development may be stopped using an aqueous solution with a low pH. For example, an aqueous solution comprising acetic acid and sulfuric acid containing a buffer and having a pH not exceeding 3.5 is preferable.

A buffer stop bath composition comprising a mixture of sodium dihydrogen orthophosphate and disodium hydrogen orthophosphate is preferred.

[0095] Conventional fixers are used. Examples of useful fixing agents include organic sulfur compounds known as fixing agents, as well as thiosulfates, thiocyanates, and the like. The fixer may contain a water-soluble aluminum salt as a hardening agent.

The stop solution is an aqueous solution with a low pH. For example, an aqueous solution containing a buffer consisting of acetic acid and sulfuric acid is preferred.

The photographically sensitive direct positive silver halide material of the present invention comprises an internal latent image type silver halide emulsion layer, preferably a silver halide gelatin emulsion layer. However, a variety of other hydrophilic colloids can be used in place of or mixed with gelatin as the silver halide binder.

Other suitable hydrophilic colloids which can be used as binders for silver halide are synthetic, semi-synthetic or natural polymers. Synthetic substitutes for gelatin are, for example, polyvinyl alcohol, polyN-vinylpyrrolidone, polyvinylimidazole, polyvinylpyrazole, polyacrylamide, polyacrylic acid and derivatives thereof, especially copolymers thereof. Other synthetic substitutes for gelatin are latexes such as polyethyl acrylate latex. Natural substitutes for gelatin are, for example, other proteins such as zein, albumin and casein, cellulose derivatives, sugars, starches and alginates. Semi-synthetic substitutes for gelatin generally include modified natural products, such as those obtained by converting gelatin with alkylating or acylating agents, or by grafting polymerizable monomers onto gelatin, and cellulose derivatives, such as hydroxyl These are alkylcellulose, carboxymethylcellulose, phthaloylcellulose and cellulose sulfate. The presence of such other binders often has a favorable photographic effect on the formation of direct positive images. For example, the addition of latexes of polyvinylpyrrolidone and the polyethyl acrylates often directly enhances the maximum density of the positive image.

Suitable additives for improving the dimensional stability of the photographic material can also be included together with hydrophilic colloids. Suitable examples of compounds of this type include, for example, dispersions of water-soluble or sparingly water-soluble synthetic polymers, such as alkyl acrylates, alkyl methacrylates, alkoxy acrylates, alkoxy methacrylates, glycidyl acrylates, glycidyl methacrylates, acrylamides, methacrylamides, vinyl esters. , acrylonitrile, olefin and styrene polymers, or the aforementioned compounds with acrylic acid, methacrylic acid, α,
There are copolymers with β-unsaturated dicarboxylic acids, hydroxyalkyl acrylates, hydroxyalkyl methacrylates, sulfoalkyl acrylates, sulfoalkyl methacrylates and styrene sulfonic acids.

The binder must have a preferred number of functional groups capable of imparting a sufficiently resistant layer by reaction with a suitable curing agent. Such functional groups include in particular amino groups, but also carboxyl groups, hydroxyl groups and active methylene groups.

The gelatin may be lime-treated or acid-treated gelatin. The preparation of gelatin of this type is described, for example, in A. G. It is described in "The Science and Technology of Gelatin", edited by Ward and A. Coates, pages 295 et seq. The gelatin may be the enzyme-treated gelatin described in the Journal of the Japan Photographic Science Association, 1966, Vol. 16, page 30.

Various compounds can be added to photographic emulsions to prevent a decrease in sensitivity or the formation of fog that occurs during the preparation, storage or processing of photographic materials. A large number of compounds are known for this purpose and these compounds include homopolar or salt-like compounds of mercury with aromatic rings or heterocycles such as mercaptotriazole, mercury single salts, sulfonium mercury double salts. and other mercury compounds. Other suitable stabilizers are azaindenes, preferably tetra-azaindenes or penta-azaindenes, especially those substituted with hydroxyl or amino groups, such as 4-
Hydroxy-6-methyl-1,3,3a,7-tetra-
It is azainden. This type of compound is Z. Wiss.
Photogr. Photohhys. Photo
chem. Beer, Vol. 47, pp. 2-27, 1952. Other suitable stabilizers are in particular heterocyclic mercapto compounds, such as 1-phenyl-5-mercaptotetrazole, 3-methylbenzothiazole, quaternary
benzothiazole derivatives and benzotriazoles. Specific examples of stabilizers can be found in the 1966 3rd edition of ``Theory of Photographic Processes'' by K. It was described by Mace, citing the paper that first reported such a compound.
In addition, in particular, US-A1758576, 211017
8, 2131038, 2173628, 2304962
, 2324123, 2394198, 2444605,
2444606, 2444607, 2444608, 2
476536, 2566245, 2694716, 26
97040, 2697099, 2708162, 272
8663, 2728664, 2728665, 2824
001, 2843491, 2886437, 30525
44, 3137577, 3220839, 322623
1, 3236652, 3251691, 3252799
, 3287135, 3326681, 3420668 and 3622339; GB-A893428, 4037
89, 1173609 and 1200188.

The silver halide emulsions may also contain other ingredients such as development accelerators, wetting agents and hardening agents. The binder of the silver halide emulsion and/or other hydrophilic colloid layers, particularly when the binder used is gelatin, can be hardened using suitable hardeners, including epoxide-type hardeners. 1, ethyleneimine type, vinyl sulfone type, etc.
3-vinylsulfonyl-2-propanol, chromium salt,
For example chromium acetate and chromium alum, aldehydes such as formaldehyde, glyogyzal and glutaraldehyde, N-methylol compounds such as dimethylol urea and methylol dimethylhydantoin, dioxane derivatives such as 2,3-dihydroxydioxane, activated vinyl compounds such as 1,3 , 5-triacryloyl-hexahydro-s-triazine, active halogen compounds such as 2,4-dichloro-6-hydroxy-s-triazine, and mucohalogen acids such as mucohydrochloric acid and mucophenoxyhydrochloric acid. These curing agents can be used alone or in combination. The binder is European Patent Application Publication No. It can also be cured by fast-reacting curing agents such as carbamoylpyridinium salts and phosphorus compounds described in US Pat. No. 0,408,143.

Compounds that liberate iodide ions, such as potassium iodide, can be included in silver halide photographic emulsions. Furthermore, the developer used in the method of the invention may contain iodine ions.

The photographic direct positive materials of this invention may contain water-soluble dyes as filter dyes or in the hydrophilic colloid layer for various other purposes such as anti-irradiation or anti-halation. Such dyes include oxonol dyes, hemioxonol dyes, styryl dyes, merocyanine dyes, cyanine dyes and azo dyes. Among these, oxonol dyes, hemioxonol dyes and merocyanine dyes are useful.

When the hydrophilic colloid layer of the photographic direct-positive material of the invention contains dyes or UV absorbers, these compounds may be added to cationic polymers, such as GB-A 1468460 and 685475, US-A.
A2675316, 2839401, 2882156,
3048487, 3184309, 3445231 and 3986875 and by the polymers described in DE-A1914362.

The photographic direct positive materials of the invention may contain various types of surfactants in the photographic emulsion layer or in at least one other hydrophilic colloid layer. Suitable surfactants are saponins, nonionic surfactants such as alkylene oxides, such as polyethylene glycol condensation products, polyethylene glycol condensation products, polyethylene glycol/polypropylene glycol condensation products, polyethylene glycol alkyl ethers or polyethylene glycol alkyl allyl ethers. , polyethylene glycol esters, polyethylene glycol sorbitan esters, polyalkylene glycol alkylamines or alkylamides, silicone-polyethylene oxide adducts, glycidol derivatives, fatty acid esters of polyhydric alcohols and alkyl esters of sugars, carboxyl groups, sulfo groups, phospho groups, Anionic activators containing acid groups such as sulfate or phosphate ester groups, amino acids,
Amphoteric surfactants such as aminoalkylsulfonic acids, aminoalkyl sulfates or phosphates, alkyl betaines and amine-N-oxides, and alkylamine salts, aliphatic, aromatic or heterocyclic quaternary ammonium salts, aliphatic or heterocyclic cationic activators such as phosphonium salts or sulfonium salts. Such surfactants may be used for a variety of purposes, such as as coating aids, as antistatic compounds, as slideability improving compounds, as dispersion emulsifier promoting compounds, as compounds that prevent or reduce tackiness, etc. It can also be used as a compound to improve photographic properties, for example to improve contrast and accelerate development.

Development can be accelerated by various compounds, preferably U
S-A3038805, 4038075 and 4292
molecular weight of at least 40 as described in 400
This can be carried out with the help of 0 polyalkylene derivatives.

The photosensitive direct positive material of the present invention also comprises:
Various other additives may be included in the silver halide emulsion layers, such as UV absorbers, matting or spacing agents, wetting agents and plasticizers.

Suitable UV absorbers are particularly US-A353
Aryl-substituted benzotriazole compounds described in 3794, US-A 3314794 and 3352681
4-thiazolidone compound described in Japanese Patent Publication No. 46-2
784 (1971), cinnamic acid ester compounds described in US-A 3705805 and 3707375, US-A 404522
butadiene compounds described in 9 and US-A37
It is a benzoxazole compound described in No. 700455.

Suitable spacing agents are for example US-A 46147
The finely divided silica particles and polymer beads described in 08.

[0112] Generally, the average particle diameter of the spacing agent is 0.2 to 1.
It is 0 μm. The spacing agent may be soluble or insoluble in alkali. Alkali-insoluble spacing agents usually remain permanently in the photographic material, whereas alkali-soluble spacing agents are usually removed from the photographic material in an alkaline processing bath. Suitable spacing agents can be made especially from polymethyl methacrylate, copolymers of acrylic acid and methyl methacrylate, and hydroxypropyl methylcellulose hexahydrophthalate. Other suitable spacing agents are US-A
4614708.

Matting agents and/or lubricants are added to the emulsion layer and/or protective layer of the photographic direct positive material of the invention. A suitable matting agent is, for example, 0.2 to 6
These are water-dispersible vinyl polymers such as polymethyl methacrylate with a suitable particle size of μm and inorganic compounds such as silver halides and strontium barium sulfate. Lubricants are used to improve the slideability of photographic materials. Preferred examples of lubricants include liquid paraffin, waxes such as esters of higher fatty acids, polyfluorinated hydrocarbons or their derivatives, polyalkylpolysiloxanes, polyarylpolysiloxanes, polyalkylarylpolysiloxanes and alkylene oxide addition derivatives thereof. Silicones such as

A wide variety of photographic supports can be used for the photosensitive direct positive materials of this invention. The silver halide emulsion can be coated on one or both sides of the support. For use in COM films, the support must be highly antistatic and therefore highly conductive. Suitable supports are, for example, cellulose acetate films such as cellulose triacetate and cellulose diacetate, cellulose nitrate films, polyethylene terephthalate films and polystyrene films.

First step for creating a direct positive image according to the present invention
In step , the photographic direct positive material is imagewise exposed. This exposure is at least 0.1 mJ/m2
A high intensity exposure for a short period of time, e.g. 10-5 to 10-8 seconds, such as that typically utilized in COM recorders, to light in the wavelength range of about 440 to about 480 nm at an intensity of .

In the second step for producing a direct positive image, the imagewise exposed silver halide material is immersed, for example, in a developer solution. For example, imagewise exposed silver halide material is introduced into a tray containing a developer solution.

The developer may be partially or completely contained in the photographically sensitive silver halide material. The developer may be included in the preparation of the material by means of a processing agent that moistens the photographic material prior to development of the direct positive image, or at a later stage. In this way, the surface developer can be transformed into a mere alkaline solution substantially free of developer. Such alkaline aqueous solutions are often referred to as "activators" and offer the advantage of having longer activity, ie being consumed more slowly. The pretreatment solution may contain at least a portion of the development nucleating agent, and may otherwise contain other components that should be included in the developer solution. Wetting a photographic material with a processing solution containing a development nucleating agent and/or a concentration-enhancing compound can be accomplished by dipping one side of the material or by moistening one side of the material, e.g. by a lick roller, e.g. by applying a paste in a pod. This can be done by any conventional method such as painting or spraying.

According to another second step for creating a direct positive image, the imagewise exposed silver halide material is exposed to high intensity light to fog said imagewise exposed silver halide material. After flushing the entire surface, it is developed with a surface developer.

The photographically sensitive silver halide materials used in the method of the invention are particularly utilized for COM recording, but especially for graphic arts recording, silver salt diffusion transfer, microfilm recording, laser recording, It is useful in cathode ray recording and other methods where direct positive imaging can be performed in photo-ipset methods.

[0120]

EXAMPLES The invention will be explained in more detail with reference to the following examples. However, the invention should not be construed as limited to these examples.

Example 1 An internal latent image type direct positive silver halide gelatin emulsion was prepared by converting a silver halide emulsion in the presence of water-soluble bromide and iodide to form a core consisting of silver chloride (4 mol %) and bromide. It was prepared by producing grains with a shell of silver iodide (95/1 mole %). The average diameter of the particles is 0.
It was 4 μm. The silver halide emulsion has the following structural formula (XV
) was sensitized by cyanine ortho sensitizing dye.

[0122]

[C6]

[0123] The amount of sensitizer is 300 m per 200 g of silver nitrate.
It was g.

Dispersion of the development nucleating agent corresponding to structural formula
This was done by passing the mixture through a sand mill for 120 minutes.

This dispersion has a concentration of 200 g per 5 g of silver halide.
It was added to the silver halide emulsion at a concentration of mg.

The prepared emulsion was coated on a support made of cellulose triacetate at a rate of 6.5 g/m2 of silver halide and dried.

One sample of the resulting photosensitive material was purchased from E.P., 45 William Street, Wellesley, Massachusetts 02181, USA. G. &G. ING. Exposure for 10-5 seconds to white light emitted by a flashlight U460 commercially available from the company and then 60 seconds at a temperature of 35 °C with a hydroquinone type developer (bath).
Developed for seconds. The developer at this time contained the following components.

[0128] Demineralized water

700ml hydroquinone

24g 3-dimethylaminopropanol
40ml sodium sulfite
110g sodium hydroxide
18g
sodium carbonate

40g potassium bromide

3g Delicious water required to make the total volume 1L
(pH value 11.5)

0129
The sensitivity measurement curve obtained for the first sample is shown in the attached FIG. 1.

A second sample of the same photosensitive material was treated with E. G
．． &G. The white light emitted by the aforementioned flashlight U460, commercially available from
53 and then developed in the same manner as the first sample.

The sensitivity measurement curve obtained for the second sample is shown in attached FIG. 2.

Maximum concentration of samples 1 and 2 (Dmax
) values, minimum density (Dmin) values, gradation and speed were measured and listed in Table 4. The numbers shown for speed are expressed as logE. The larger the speed value, the lower the speed.

[0133]
Table 4 Sample Dmi
n Dmax Speed Gradation Exposure 1
11 194 180
1.15 10-5 seconds 2
11 214 10
2 2.15 10-2 seconds

In order to obtain suitable maximum density and speed values with shorter development times, for example 45 seconds, it was necessary to change the development nucleating agent. For example, as a development nucleating agent, 1-formyl-
When 2-phenylhydrazine was used, the development time could be made shorter than when using the development nucleating agent corresponding to structural formula X. The results obtained for sample 3 are shown in Table 5. Sample 3 was similar to Sample 1 except that 1-formyl-2-phenylhydrazine was used as the development nucleating agent instead of the development nucleating agent corresponding to Structure X. Sample 3 sensitized with dye XV was
Exposure for 10-5 seconds with white light emitted by flashlight U460, development time 45 seconds at 35°C.
It was a second.

[0135]
Table 5 Sample Dmi
n Dmax Speed Gradation 3 12
145 180 1.66

0136
The tone values obtained using these ortho-sensitized emulsions were too low for COM applications requiring values of at least 1.70.

Example 2 An internal latent image type direct positive silver halide gelatin emulsion was prepared by converting a silver halide emulsion in the presence of water-soluble bromide and iodide to form a core consisting of silver chloride (4 mol %) and bromide. It was prepared by producing grains with a shell of silver iodide (95/1 mole %). The average diameter of the particles is 0.
It was 4 μm. The silver halide emulsion is as follows: Batch 2A
, was divided into three equal portions called Batch 2B and Batch 2C.

Batch 2A remained unsensitized. Batch 2B was sensitized with a cyanine ortho sensitizing dye corresponding to structural formula XV described above; Batch 2C was sensitized with a cyanine ortho sensitizing dye corresponding to structural formula XV1 below.

[0139]

[C7]

The amount of sensitizer used in Batch 2B and Batch 2C was 300 mg per weight of silver halide equivalent to 200 g of silver nitrate.

A dispersion of the development nucleating agent 1-formyl-2-phenylhydrazine was added to each of batches 1 to 3 at a concentration of 200 mg/5 g of silver halide.

The resulting batches 2A to 2C contained 6.5 g/m2 of silver halide on a cellulose triacetate support.
It was applied and dried at a ratio of

Each of batches 2A to 2C was 10 liters of white light emitted by the aforementioned flashlight U460.
−5 seconds and then 45°C at a temperature of 35°C using the hydroquinone type developer described in Example 1.
Developed for seconds.

[0144] Dmax values and Dmin of batches 2A to 2C
Values, gradients and speeds were measured and listed in Table 6. The numbers shown for speed are expressed as logE. The larger the speed value, the lower the speed.

[0145]
Table 6 Batch
Dmin Dmax Speed
Gradation 2A 0.08
1.41 194 1.22
2B 0.12 1.45
180 1.66 2
C 0.09 1.38 213
1.26

The results listed in Table 6 show that although the maximum density and gradation are slightly improved by this prior art, they remain substantially unsatisfactory for COM applications.

Example 3 Three batches of silver halide emulsions were prepared, coated, exposed and developed as described in Example 2.

Batch 3A remained unsensitized and was therefore comparable to Batch 2A of Example 2.

Batches 3B and 3C were sensitized with varying concentrations of merocyanine dye MO1 from Table 1. The amounts of sensitizer used are given in Table 6 as mg per weight of silver chloride equivalent to 200 g of silver nitrate.

Dmax value, Dmin of batches 3A to 3C
Values, gradients and speeds were measured and listed in Table 7.

[0151]
Table 7 Batch MO1 mg
Dmin Dmax Speed
Gradation 3A 0
0.08 1.41 19
4 1.22 3B 168
0.14 1.98 19
0 1.66 3C 420
0.16 1.66 18
0 1.87

The results listed in Table 7 show that the maximum density and gradation obtained using merocyanine dyes are better than those obtained using cyanine dyes.

Example 4 A core-shell silver halide emulsion was prepared by double jet precipitation. The cores were 0.24 μm chemically sensitized with 4.1 mg sodium thiosulfate, 7.6 mg HAuCl4·4H2O and 5.8 mg p-toluenethiosulfonic acid sodium salt for 4.5 h at 50 °C. It is composed of octahedral silver bromide grains. Octahedral particles with a particle size of 0.3 μm were obtained after precipitation of the shell onto the core. The core-shell emulsion produced was 2.2 mg.
of sodium thiosulfate, 1 mg of HAuCl4 4H
4 by 2 O and 2 mg ammonium thiocyanate.
Chemically sensitized for 4 hours at 6°C. The resulting silver halide emulsion was divided into four portions designated batches 4A, 4B, 4C and 4D.

These batches were sensitized with varying concentrations of merocyanine dye MO1 as shown in Table 5. The amounts of sensitizer used are shown in Table 8 below in mg per mole of silver nitrate. Each batch contained 6.64 mmol of the development nucleating agent 1-formyl-2-phenylhydrazide per mole of silver nitrate.

Each of the prepared batches A-D was shown as silver nitrate on a polyester film support.
A silver coverage of g/m2 was applied. 1.04g/m2
A protective layer containing gelatin was applied and formaldehyde was used as a hardening agent.

Each of the prepared batches A to D was exposed for 10-5 seconds to white light emitted by the aforementioned flashlight U460 and then developed for 45 seconds at a temperature of 35° C. using a hydroquinone type developer. It was done. This developer contained the following components.

[0157] Demineralized water

500ml p-N methylaminophenol
15g sodium hydroxide

17.5g Sodium sulfite

110g 41% aqueous solution of ethylenediaminetetraacetic acid
2ml sodium carbonate

40g sodium bromide
10g
hydroquinone

24g oxalic acid

2g 2-methylaminoethanol
40ml Demineralized water (pH 11.7) required to bring the total volume to 1L

The Dmax values, Dmin values and speeds of Batches A-D were determined and listed in Table 8.

[0159]
Table 8 Batch
MO1 mg Dmin Dmax
Speed 4A*
224 0.2
2.7 156 4B
449 0.04
0.9 118 4C
673 0.08 1
．． 7 130 4D
898 0.08 2.
8 147* This means that a development time of 90 seconds is required to obtain a maximum density of 2 or more in this particular case.

The results listed in Table 8 show that high concentrations of merocyanine dye improve peak density. The reversed images obtained in batches B to D are also batch A.
The concentration was lower than that of A reversal image is a negative image obtained when the exposure is extended (overexposure).

Example 5 Six batches of silver halide emulsions were prepared, coated, exposed and developed as described in Example 2.

Batch 5A remained unsensitized and was therefore equivalent to Batch 2A of Example 2.

Batches 5B, 5C, 5D, 5E and 5F
are merocyanine dye MO1 and rhodacyanine dye RO1
Sensitization was achieved by combining different concentrations of The amounts of sensitizer used are shown in Table 9 as mg per weight of silver halide equivalent to 200 g of silver nitrate.

[0164] Dmax values and Dmin of batches 5A to 5F
Values, gradients and speeds were measured and listed in Table 9.

[0165]
Table 9 Batch MO1mg
RO1mg Dmin Dmax Speed
Gradation 5A 0
0 0.08 1.41 194
1.22 5B 168 1
21 0.14 2.85 215 2.
63 5C 294 121
0.14 2.70 210 2.50
5D 420 121
0.15 2.75 208 2.94 5E
630 121 0.2
4 2.88 207 3.12 5F
168 283 0.15
2.70 230 3.40

The results listed in Table 9 show that the maximum density and tone values obtained with the combination of merocyanine and rhodacyanine dyes are considerably better than those obtained with cyanine dyes.

[Brief explanation of the drawing]

FIG. 1 shows a sensitivity measurement curve of a first sample of Example 1.

FIG. 2 shows the sensitivity measurement curve of the second sample of Example 1.

Claims (7)

[Claims] 1. A photographic light-sensitive material comprising a support and at least one photographic emulsion layer containing unfogged internal latent image type silver halide grains.
2 for a short time of 10-5 to 10-8 seconds at a high intensity of about 44
imagewise exposing to light in the wavelength range from 0 to about 480 nm; and (a) developing the imagewise exposed material with a surface developer in the presence of at least one development nucleating agent; or (b) A method for enhancing the maximum density and tonality of a direct positive image obtained by an overall light flashing step to overlay said imagewise exposed material before its development in a surface developer, wherein said photographic emulsion layer comprises at least one A method characterized in that it contains a seed merocyanine dye. 2. The photographic emulsion layer also contains at least one rhodacyanine dye.
the method of. 3. The at least one development nucleating agent is in the at least one photographic emulsion layer, in a hydrophilic colloid layer in water-permeable relationship with the photographic emulsion layer, or in the surface developer. 3. A method according to claim 1 or 2, characterized in that: 4. A method according to claim 1, wherein the at least one development nucleating agent is 1-formyl-2-phenylhydrazine. 5. A photographic light-sensitive direct positive material for producing direct positive images, said material comprising a support and at least one film containing non-foggable internal latent image type silver halide grains and a development nucleating agent. In a photographic direct positive material comprising two light-sensitive emulsion layers, said photographic emulsion layer comprises at least one light-sensitive emulsion layer.
Photographic light-sensitive direct positive material characterized by containing a merocyanine dye of seeds. 6. The photographic emulsion layer also contains at least one rhodacyanine dye.
A photographic photosensitive direct positive material. 7. The development nucleating agent is added as a dispersion to the emulsion layer or to a hydrophilic colloid composition forming a hydrophilic colloid layer in water-permeable relationship with this layer. The photosensitive direct positive material according to claim 5 or 6.