JPH02160230A - Internal image generation emulsion for - Google Patents

Abstract

PURPOSE: To produce an emulsion having high sensitivity for a direct positive by coating a cubic and/or octahedral core with silver iodide or silver bromide iodide and then covering the core with a silver bromide shell having faces of a cube and/or octahedron. CONSTITUTION: The silver halide core is cubic or octahedral and the surface of the core emulsion is wholly or partly covered with a layer of silver iodide or silver bromide iodide. This coating process can be performed by a general precipitation method by adding a soln. of iodide and silver salt to the core emulsion under controlling. Preferably, the amt. of iodide necessary to coat the core is 0.5 to 10mol% of the core emulsion. The coated core is then covered with a silver bromide shell having faces of a cube and/or octahedron. The shell is preferably produced by a direct precipitation method of silver bromide. The thickness of the shell is preferably >=0.04μm. Thereby, an emulsion having high sensitivity for a direct positive can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to novel photographic internal imaging emulsions containing layered silver halide crystals and capable of producing internal latent images.

Photographic internal imaging emulsions containing layered silver halide crystals are known in the art. For example, in U.S. Pat. Silver halide emulsions containing crystals are taught. Such emulsions can be used in the production of direct positive images. Imagewise exposure of these emulsions produces internal latent image sites at the exposed sites on the surface of the core. The shell protects these internal image areas from development by surface developers. However, when this surface developer is developed under known conditions, i.e., in the presence of nucleating or fogging agents, or by uniform flash exposure before or during development, unexposed silver halide crystals are , and an inverted image is obtained. As a result, a direct positive image is obtained.

Direct positive images are also available in U.S. Pat. No. 4,704.3.
It can also be produced using the emulsion disclosed in No. 49. These emulsions also contain layered silver halide crystals with a chemically sensitized core encapsulated by a shell that is first subjected to sulfur/gold sensitization followed by treatment with iodide ions. There is. The great advantage of this emulsion is that positive images can be obtained directly (without the use of nucleating agents or diffuse post-exposure). However, the preparation of this emulsion requires chemical sensitization of the core and shell and Since the thickness of the shell must be precisely adjusted, a complicated optimization process is involved.

It is therefore an object of the present invention to provide a simple method for producing direct positive emulsions. This purpose is
This is achieved by starting from a novel internal imaging emulsion containing layered silver halide crystals and capable of producing an internal latent image. Surprisingly, the core of such silver halide crystals is cubic/octahedral.
It has been found that chemical sensitization of the core is not required if the core has a hedral) shape and all or part of the surface of the core is coated with silver iodide or silver bromoiodide.

This allows the optimization process described above to be substantially simplified.

Therefore, the present invention provides that the silver halide core is cubic/
having an octahedral shape, such a cubic/octahedral core being coated with silver iodide or silver bromoiodide and encapsulated with a silver bromide shell having cubic and/or octahedral faces. The present invention relates to a photographic internal image-forming emulsion comprising a layered structure of silver halide crystals and capable of producing an internal latent image.

The present invention further provides a method of making a direct positive emulsion using the internal imaging emulsion of the present invention, the direct positive emulsion thus obtained, a color development, a die diffusion transfer step and a silver dye bleaching step comprising such a direct positive emulsion. The present invention relates to a photographic recording material, a photographic member, a film member, and a method for producing a direct positive image characterized by using such a recording material.

In the internal imaging emulsions of the present invention comprising a layered core, the core is of cubic/octahedral shape, i.e. (10
The dimensions of the cube planes of the core, which must be of the 0) and (111) planes, can be varied within wide limits.

Preferably, the core consists of silver bromide or silver chlorobromide.

These core emulsions can be prepared by methods known per se, for example, G.
rund-1agen der photography
ischen Prozesse mitSilber
halogeniden (Principles of
Photographic Processes wit
h 5ilver Halidesl', vol.
3°p, 631-2.

In a preferred embodiment, the core has a narrow crystal size distribution, i.e., the coefficient of variation in crystal size is less than 20% (the coefficient of variation is 100 times the standard deviation of crystal sizes divided by the average crystal size). ).

The surface of the core emulsion is coated, in whole or in part, with a layer of silver iodide or silver bromoiodide. This coating can be carried out by conventional deposition methods, for example by controlled addition of iodide and silver salt solutions to the core emulsion. Preferably, the amount of iodide needed to coat the core is from 0.5 to 10 mole percent of the core emulsion.

The coated core is encapsulated with a silver bromide shell having cubic and/or octahedral surfaces.

This shell is preferably produced by a direct silver bromide deposition method, such as a controlled double jet method. The thickness of the shell must be large enough to substantially prevent the minimum density from becoming high and to substantially prevent the creation of a negative image of the overexposed areas, called re-inversion. ,Also.

It depends on the solubility of the surface developer used in the silver halide. The thickness of the shell is preferably 0.04 pm or more.

Once the silver halide shell is manufactured, e.g. Re5e
arch Disclosure No. 17,64
3.5ection IIA.

(December 1978), the emulsion can be removed from the water-soluble salts by known washing methods.

However, if considered necessary, a washing step can also be carried out after depositing the core emulsion.

When the internal imaging emulsions of the present invention are coated onto a support to form a layer, no image is formed when exposed to light and developed in a surface developer (line ■ in Figure 1). A direct positive image is not obtained until the shell of the silver halide crystals is similarly coated with silver iodide or silver bromoiodide and converted into a direct positive emulsion, preferably before this coating with gold or silver bromoiodide. Further sensitize the shell with gold and sulfur (Figure 1
line ■).

Photographic direct positive materials containing such emulsions can be used in a simple manner, i.e. by exposure and development in a surface developer, to produce good results as described in U.S. Pat. No. 4,704,349. Quality direct positive images are produced. There is no need to use nucleating or fogging agents or to provide a uniform second exposure during development.

However, the internal imaging emulsions of this invention can also be used to produce direct positive images when the silver bromide shell of the silver halide crystal is sensitized with gold or gold and sulfur alone. However, in this case the usual methods of developing the corresponding direct positive materials (methods using fogging agents or a second exposure) have to be used.

If the cubic/octahedral core present in the internal imaging emulsions of the present invention is replaced by a cubic or octahedral crystal structure,
Even with chemical sensitization and coating of the shell with iodide, a direct positive image is not obtained, but only a negative image with strong capri (line ■ in Figure 1).

The direct positive emulsion of this invention includes a dispersion medium in which silver halide crystals are dispersed. The dispersion medium of the direct positive emulsion layer and other layers of the photographic member may contain various colloids, alone or in combination, as binders or dispersants. Preferred binders and dispersants such as gelatin and gelatin derivatives include, for example, R
e5earchDisclosure, 17,643
．． 5ection IX.

Photographic members and film members made with the direct positive emulsion of the present invention may be prepared using known hardeners such as Re5earch.
Disclosure, 17,643.5ectio
It can be cured by what is known as nX to allow processing at elevated temperatures.

Stabilizers, drag agents, reagents for reducing pressure sensitivity, stabilizers for latent images, and photographic emulsions to protect against instability that may alter the properties of the direct positive material. Similar modifiers commonly used in manufacturing can be added. Such modifiers include, for example, Re
5earchDisclosure, 17,643
．． (December 1978) 5ection VI. Many anti-brittle agents that are effective in emulsions can also be used in the developer. This type of drag agent is
For example, C, E published by Macmillan
, in Mees'°'The Theory of
thePhotographic Process, 2nd
Edition, 1954. 677-680.

In some cases, the direct positive materials of the present invention are
Advantageous results can be obtained when developing in the presence of certain anti-abrasive agents, such as those described in U.S. Pat. No. 2,497.917.

Alternatively, the direct positive material may be developed in the presence of a relatively high concentration, e.g. up to 5 g, preferably 1 to 3 g, per developer solution II2 of the above-mentioned anti-abrasive agents, or these compounds may be processed, e.g. 1000 mg per mole of silver
Advantageous results can be obtained by including it in the photographic recording material, preferably at a concentration of 100 to 500 mg.

Apart from the modifiers mentioned above, a number of other conventional photographic modifiers can be used in the direct positive emulsions of the present invention.

Such modifiers include, for example, Re5earch Disc
loss, No. 17,643. (1978
December) Section V, VIII, XI-
XIV, XVl, XX and XXI.

In order to obtain wider exposure latitude, the direct positive emulsions of the invention of different sensitivities can be mixed together.

To meet specific requirements, the emulsions of the invention can be used as conventional negative emulsions which produce surface images when coated with iodide by coating the shell of the crystals with iodide or by sensitizing them with gold or gold and sulfur. It can also be mixed or combined with. The latter method is particularly important for masking silver dye bleaching materials.

In its very simple form, a recording material according to the invention has one direct positive emulsion layer.

However, the recording material may include one or more direct positive emulsion layers,
as well as the top layer present in conventional photographic recording materials;
Instead of mixing the emulsions with each other as described above, which may have an adhesive layer and an intermediate layer, a similar effect can often be obtained by applying the emulsions in the form of separate layers. The use of separate emulsion layers to obtain advantageous exposure latitude is described, for example, in Zelikman and Levi's Making and
rapic Emulsions, Focal P
ress 1964, p, 234-238 and British Patent Specification No. 923045.

Furthermore, it is known that improved photographic speed can be obtained if a relatively fast direct positive emulsion and a relatively slow one are applied to a support in separate layers instead of being mixed.

Preferably, more sensitive emulsion layers are located closer to the light source than less sensitive emulsion layers. Instead of using two emulsion layers, three or more emulsion layers can also be placed on top of each other.

A wide variety of conventional supports can be used in the production of the direct positive images of the present invention. These include polymeric films, wood fibers, e.g. paper, metal foil supports, glass supports and supports made from ceramic materials, with adhesive and antistatic properties, dimensional properties, if desired. , one or more adhesive layers are provided to improve the antihalation properties and/or other properties of the support surface. Such supports are, for example, Re5earchD
isclosure No. 17.643. (1
December 1, 978. 5ection XVII.

The direct positive recording material of the invention is, for example, Re5earc
h Disclosure No. 17,643.5
The advantages that can be obtained by the present invention are, in particular, that the spectral sensitizers present can be exposed by conventional methods such as those described in Section XVIII. This will become clearer if you perform a different exposure. If the photographic recording material is for recording in the blue, green, red or infrared region, a spectral sensitizer is present which absorbs in the blue, green, red or infrared region of the spectrum. In the case of black-and-white recording materials, it has proven advantageous to sensitize the recording material orthochromatically or panchromatically in order to shift the sensitization region into the visible spectrum.

The synchrotron radiation used for exposure may be incoherent light (of random phase) or coherent light (of uniform phase generated by a laser).
Furthermore, the recording material can be imagewise exposed with widely different intensities of light sources at normal, elevated or reduced temperatures and/or pressures. This can be done continuously or intermittently. Exposure times are determined, for example, by T. H. James, “the Theory of
the Photographic Process
, 4th edition f1977), 4.6.17.18 and 2
It can be determined by conventional known sensitivity measurement methods, which are described in more detail in Section 3.

After exposure, the photosensitive silver halide of the recording material is developed into a visible image in the usual manner by contacting the silver halide with an alkaline aqueous solution containing a developer compound.

The developer used to develop silver halide is a surface developer.6 In this specification, the term "surface developer" refers to the surface developer that exposes the core of the surface latent image of the silver halide grains. It is intended to include a developer that does not expose substantially all of the internal latent image nuclei in the emulsion that produces the internal latent image under the conditions normally used for developing silveride emulsions. Generally, conventional silver halide developer compounds or reducers can be used in the surface developer, but
The developer bath or developer composition typically contains a silver halide solvent, such as water-soluble thiocyanates, water-soluble thioethers, thiosulfates, and ammonia, that destroys or dissolves the silver halide grains to expose the internal image. It is substantially free of. Although the presence of relatively small amounts of halide ions in the developer is desirable and is often introduced into the emulsion as a halide-dissociating compound, high concentrations of iodide or iodide-dissociating compounds are avoided to prevent destruction.

Examples of typical silver halide developer compounds that can be used in the developer include hydroquinones, pyrocatechols, aminophenols, 3-pyrazolidones, ascorbic acid and its derivatives, reductones, phenylenediamines or It is a combination of these. The developer compound can introduce itself into the recording material and be brought into contact with the silver halide after imagewise exposure. however,
In some cases it is preferred that they be used in a developer solution or developer.

If the direct-positive material contains only gold or a direct-positive emulsion superficially sensitized with gold and sulfur, development may be carried out as described in, for example, U.S. Pat. No. 4,395,47.
This must be done in the presence of a fogging agent or by simultaneous uniform flash exposure, as described in No. 8.

Development is preferably carried out at elevated temperatures, for example in the range from 30 to 60<0>C.

Photographic recording materials and elements and film elements comprising the direct positive emulsions of the present invention are suitable for producing color images by selective decomposition or formation of dyes, such as by color development or silver dye bleaching methods. It can be used in known methods for. These methods are T
, H. James's Theory of t
he Photographic Process (1
9771, p. 335-372.

The direct positive emulsions of the present invention may also be used, for example, Re5ear
ch Disclosure No. 15,162
It can also be used in the photographic diffusion transfer method described in (November 1976).

The direct positive emulsions of the present invention are distinguished from the prior art by their easy availability, high sensitivity and wide range of applicability. They do not have a tendency to re-invert, ie do not give negative images due to overexposure, and have good storage stability.

The invention is illustrated by the following examples.

A g N
2000 ml' of a 4N solution of Os and a 4N solution of KBr
20001 dl of solution were poured by double jet method at 53° C. and pAg: 6.5.

To the 4N solution of KBr, 24 g of NH, Not and 818 of 4N NaO were added in advance.

After adding half of A g N Os and KBr, p, A
The g value was adjusted to 9.0. The precipitation was completed after 1 hour and monodisperse AgBr cubic/octahedral crystals with a particle size of 0.60P and particle size distribution: δ=4.1% were obtained. The emulsion was flocculated in a known manner, washed and redispersed so that 1 kg of emulsion contained 1 mole of Ag and 50 g of gelatin.

2. While stirring well, add 301d of 1.0M solution of KI to 50% of the core.
Core emulsion 2000 at 3°C, pH 6.3, pAg: 8.5
After 5 minutes, the pAg was adjusted to 6.5 by adding approximately 30 mL of a 160M solution of AgNOs.

3. A g N of the reduced core according to
4M solution of Os 1000WJ and 4M solution of KBr 2
000- was poured into 2060 g of coated cubic/octahedral core emulsion at pH 5.0% PAg: 6.5.53°C by controlled double jet process.

Monodisperse cubic crystals were obtained with a particle size of 0.76 Fl and particle size distribution: δ=2.5%.

These crystals have a cubic/octahedral crystal shape.
It had an inner layer of g B r l-x I x. These had internal sensitivity but no surface sensitivity. The emulsion was deionized and redispersed as described in Step 1.

NagS*Os1.34v icromillimol and HAuC
j2.2.5 micrommol.

Cubic emulsion i 000g was chemically sensitized at 65°C, pH 6.3, pAgnia, 5 for 90 minutes.

Reduce temperature to 40°C and pH to 6.5.

After adjusting the pAg to 8.5, add KI while stirring well.
Pour 250 - of a 1M solution of A g N
250 - of a 0.1M solution of Os was poured.

The coating is applied to the support and, after exposure through a stepped optical wedge, is developed in a surface developer of the composition shown in the table below (3
9° C. for 1 minute) and this emulsion had good sensitivity with a silver halide development rate of 96.5% in the maximum density area and a silver octaride development rate of 8.5% in the minimum density area. A direct positive image was obtained.

Potassium sulfite 37 g Sodium sulfite 15 g Phenidone 2
3g hydroquinone
15 g potassium metaborate
11 g boric acid 7
．． 7g ascorbic acid 12g
Potassium bromide 2g Benzotriazole 0.9g Ethyl cellosolve 57g The total amount was made up to 1000-g with water.

0.76.0.69F, shell thickness 0.13°0.08.
It contained cubic crystals with 0.045 Fl. 2 per mole of silver halide as described in Example 1.
．． 65 using 5 micrommol HAuCI24
After chemical sensitization at 0.degree. C., pH 6.3, pAg: 6.5, 2.8 mol% of iodide was coated on the surface.

The support was coated with the three emulsions, exposed and processed as in Example 1, giving the sensitometric results shown in Table 1 below.

Following the procedure described in Example 1 of Rj2Nigiel, (a) 2 moles, (b) 1 mole, (cl 0.
A 5 molar amount of cubic form of silver bromide was deposited as described in Example 1 onto a core emulsion with an iodine coated side.

The three emulsions each had an edge length of 0.87, with decreasing sensitivity and increasing minimum density as shell thickness decreased. However, the minimum density can be lowered by spectral sensitization (Example 4).

3: H, H,
NH4NOx in 050- and IM-NaOH13-
4g was added at 40°C.

After 5 minutes, add 100M of 0.1M solution of KI and add 5 minutes
After 10 minutes, the excess halide was neutralized with a 10-M solution of AgNOs.

The temperature was raised to 55°C and the Ag was adjusted to 9.01.
Next, a 2M solution of A g N Oa 750 Wd! , and further NH<No*6g and IM-NaOH19 points 5-
750 - of a 2M solution of KBr containing was poured by controlled double jet method.

The emulsion was flocculated, washed and redispersed so that 1 kg of emulsion contained 5% gelatin and 1 mole of silver halide, with a cubic equivalent crystal edge length of 0.818 F and grain size distribution: δ = ±2.8. A monodisperse cubic/octahedral core-shell emulsion with %.

2.5 micrommol HA per mole AgBr
u Using C124, temperature 65°C, pH 6.3 and p
Surface aging was performed at Ag:6.5. Although this ripening already produced a direct positive image, further surface treatment with potassium iodide as described in Example 1 increased the sensitivity of the direct positive emulsion by a factor of two.

The following photosensitivity measurement results were obtained.

Photosensitivity: 4.6re1. The emulsion of Example 2 was spectrally sensitized with a green sensitizer of the following formula: 4.8 mg/g of Ag of log E Dx: 96% D, . . . 11: 3% 4:. This emulsion was deposited on a polyester support at 1.2 g/m
Table 2 shows the green sensitivity values E( green) and D mall and D 111111
LD@@z and 11 are expressed as percent developed silver).

Two emulsions were prepared: a silver bromide emulsion having cubic crystals with a (dl edge length of 0.6P) and a silver bromide emulsion having octahedral crystals with the same volume as the tel cubic crystals.

First, the two emulsions were surface coated with iodide as described in Example 1 and then a shell of silver bromide was deposited.

The emulsion was processed as in Example 1 to produce a negative image. Even after chemical surface treatment and iodide coating, only negative images with significant capri and no direct positive images were obtained.

6: (111) of the core emulsion by varying the time to raise the pAg value of 6.5 to 9.0 in a simple manner.
The surface ratio of can be changed to (100).

In this method, two emulsions F and G with different surface ratios of (111) and (100) were prepared as described in Example 1. The results are shown in Table 3, and the r value is I)
It shows what percentage of the core emulsion had already been deposited when Ag was changed from 6.5 to 9.0.

Two core emulsions F and G were processed similarly to steps 2 and 4 in Example 1. The results of sensitometric measurements of the direct positive emulsion thus obtained are shown in columns 5 to 7 of Table 3. These results showed that the surface ratio of (100): (111) could be varied over a wide range. .

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the characteristics of the image forming emulsion of the present invention. ■... Characteristics when the internal image-forming emulsion of the present invention is coated on a support to form a layer: ■... After coating the shell with gold or gold and sulfur, the shell is coated with silver iodide or Characteristics when coated with silver bromoiodide; ■ Characteristics when the cubic/octahedral core is replaced with a cubic or octahedral crystal form. Fig. 1 rel, log E

Claims (15)

[Claims] (1) The silver halide core is cubic/octahedral (cubo
-octahedral) shape, such a cubic/
Layered silver halide, characterized in that an octahedral core is coated with silver iodide or silver bromoiodide and is encapsulated by a silver bromide shell with cubic and/or octahedral faces. A photographic internal imaging emulsion containing crystals and capable of producing an internal latent image. 2. The photographic internal imaging emulsion of claim 1, wherein the cubic faces of the silver halide core constitute 15 to 95% of the total surface area of the silver halide core. (3) The photographic internal image forming emulsion according to claim 1, wherein the coefficient of variation of the silver halide crystal diameter is less than 20%. 4. The photographic internal imaging emulsion of claim 1, wherein the shell has a thickness of at least 0.04 μm. 5. A photographic internal imaging emulsion according to claim 1, wherein the amount of iodide required to coat the silver halide core is from 0.5 to 10 mole percent of the core emulsion. 6. A photographic internal imaging emulsion according to claim 5, wherein the amount of iodide required to coat the silver halide core is from 1 to 5 mole percent of the core emulsion. (7) A method for producing a direct positive emulsion, characterized in that the silver halide shell of the silver halide crystals of the internal image-forming emulsion according to claim 1 is coated with silver iodide or silver bromoiodide. 8. The method of claim 7, wherein the silver bromide shell is sensitized with gold or gold and sulfur before coating. (9) A method for producing a direct positive emulsion, characterized in that the silver bromide shell of the silver halide crystals of the internal image-forming emulsion is subjected to sensitization with gold or gold and sulfur. (10) The core of silver halide is cubic/octahedral.
o-octahedral) shape, such cubic/octahedral core being coated with silver iodide or silver bromoiodide;
Silver halide in a layered structure, characterized in that it is encapsulated by a silver bromide shell with cubic and/or octahedral faces, which shell is also coated with silver iodide or silver bromoiodide. A photographic direct positive emulsion that contains crystals and is capable of producing an internal latent image. (11) The photographic direct positive emulsion according to claim 10, wherein the shell is sensitized with gold or gold and sulfur. (12) The core of silver halide is cubic/octahedral.
o-octahedral) shape, such cubic/octahedral core being coated with silver iodide or silver bromoiodide;
A layered silver halide crystal characterized in that it is encapsulated in a silver bromide shell with cubic and/or octahedral faces, and that such shell is sensitized with gold or gold and sulfur. A photographic direct positive emulsion that contains and is capable of producing an internal latent image. (13) Photographic materials for color development, dye diffusion transfer steps and silver dye bleaching steps, characterized in that they contain a direct positive emulsion according to claim 10 or 12 in at least one layer; Photographic parts and film parts. (14) A photographic material comprising a direct positive emulsion according to claim 10 in at least one layer is exposed to light, developed in a surface developer, fixed, washed and dried. Image manufacturing method. (15) A photographic material comprising a direct positive emulsion according to claim 12 in at least one layer is exposed and developed in a surface developer in the presence of a fogging agent or by simultaneous uniform flash exposure and fixed. A method for producing a direct positive image, comprising: washing, drying, and drying.