DE1772451A1 - Stabilization of photographic images - Google Patents

Description

... AGPA-GEVAE R. T'-AG 15, Mq \ ^ RQ

LEVERKUSEN

Stabilization of photographic images

This invention relates to a method of stabilizing developed photographic images, after which the after development Silver halides remaining in the unexposed areas are converted into compounds that are heat-resistant and lightfast and are moisture-proof, eliminating the need for normal fixation and washing operations.

Normal processing of photographic materials includes the development of the exposed silver halide into a silver image, the conversion of the exposed silver halide into a soluble salt by fixation, and removal both of the soluble silver salt formed as well as that used Fixing solution by washing.

It is often desirable in the shortest possible time and with to produce a photographic recording with a minimum of effort. For this reason it has been suggested the time consuming Eliminate fixation and washing processes by removing the unexposed and undeveloped silver halide of the photographic emulsion to be colorless by means of stabilizers converts light-insensitive compounds which do not have to be washed out.

109 815 / $ 162

The fundamental difference between conventional processing and stabilization processing is that while in the former the silver thiosulphate complexes formed on fixation must be washed out, in the latter the silver complexes remain in the emulsion.

In practice, ammonium thiocyanate is used as a stabilizer widely used, although it has some drawbacks. In fact, ammonium thiocyanate has a strong stabilizing effect, but the silver image has a strong tendency to fade or fade on storage, especially at high Humidity level.

In order to prevent the fading of the silver image during prolonged storage, it has been proposed to add heterocyclic thioxo compounds such as phenyl-2-tetrazoline-5-thione to the stabilizing solution to add. These compounds are generally sparingly soluble in acidic stabilizing baths, so it is it is difficult to incorporate them in the desired concentration-> abide. In addition, these compounds cannot be incorporated into the material itself in the desired concentration because they inhibit development.

It has now been found that the stabilizing effect of the stabilizer can be improved, i.e. that the loss of the Image density when storing the stabilized image can be reduced or avoided by using the stabilizing Treatment in the presence of at least one heterocyclic thioxo compound which has thioxothiol tautomerism, and has at least one sulfo group in acidic or salt form in its molecule.

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Thus, in accordance with the present invention, a method is provided

for the production of lightfast, heat-resistant and moisture-proof Images that are much less for a longer storage Tend to fade or stain by taking a photographic Material with at least one light-sensitive silver halide emulsion layer exposed, which exposed Material developed, and this material with a stabilizing Composition treated, turning the remaining unexposed silver halide into a non-photosensitive Compound is converted, characterized in that this Treatment occurs in the presence of at least one heterocyclic thioxo compound which has thi oxo thi oltau tomeri smu s, and in their molecule at least one sulfo group in acidic or salt form.

The heterocyclic thioxo compound used in the present invention en can be represented by the following general formula:

, -NH

4 ι

'-C = S

in the Z the necessary atoms to close a 5- or 6-membered heterocyclic ring or one with an aromatic Imagine a ring system of a fused heterocyclic ring, e.g. a fused benzene or naphthalene ring, preferably a benz- or naphth-imidazoline, -oxazoline- or -thia'zolin- ring, a diazoline ring, a triazoline ring, a thiadiazoline ring, an oxadiazoline ring, a tetrazoline ring, a thiadiazine ring, one

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Benz ^ hiazolotriazine ring, a pyridine ring, a Pyrimidine ring, a pyridazine ring or a triazine ring, wherein the molecule has at least one sulfo group in acidic or salt form, e.g., a salt of an alkali metal or an alkaline earth metal such as sodium, potassium and barium, a Ammonium group, an organic base such as an amine, a soluble zinc salt, etc.

Of course, the heterocyclic thioxo compounds according to the present invention can be substituted in the aromatic or heterocyclic ring or rings, provided that these substituents do not impair the image quality and the physical properties of the compounds. Examples! suitable substituents are: alkyl with a maximum of 5 carbon atoms, substituted alkyl such as hydroxyalkyl, aralkyl, substituted aralkyl, aryl, substituted aryl, alkoxy with a maximum of 5 carbon atoms, halogen such as chlorine, alkoxycarbonyl, nitro, amino, substituted amino such as acylamino, ₍ carboxyl, etc. .

The invention is particularly valuable in processing where there is at least one photographic developing agent in the photographic material is developed by means of an alkaline activating bath is accelerated, and the stabilizing solution is a solution of known stabilizers; these known stabilizers or silver complexing compounds include thiosulfates, thiocyanates, thioureas, thioglycolic acid, thiosalicylic acid, thiopyrimidines, etc. Ammonium, potassium and sodium thiocyanate are preferred.

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Examples of compounds according to the above general formula that Particularly suitable for use in the present invention include:

S = C CS-CH ₀ -CH ₀ -CH ₀ -SO ₀ K i j. 2 2 2

HN N

2. H.

S = C " ^X CS-CH ₀ -CH ₀ -CH ₀ -SO ₀ K I || 2 2 2

HN N

3. H.

HO ₀ S-CH ₀ -C '3 2 ,,,

N C = S

4. H.

^S "? H

HN-C-NH-N = C

HO ₀ S- *, - NH

⁶ · ο

«^ ^Κ ν" C = S HO ^ S-. Ϊ— NH

7. O ^ NaO ₃ S -. ^ * ^Ν , - ^ C =

. ^ h - ■ NH

8. SO

- / C = S

'i - NH

9. SO ₃ H

NH

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10. COOH

^ S "~ C = S NaO-S -, -.; NH.2H _o 0

^A1 ° HN C = S

SO ₃ Na 12.

L. X 3 ^H. O - -C = S
j ^V NH • SO ₃ Na NH I.
• i O ^
"c = s
j . ·
SO ₃ N / A V ^ - -_NH 13th HO ₃ s-1, o ^x S.
Il
C.
"NH L ^ O
^ ^v c = 3 ^Well * II-cent 14th I- S.
Il
c 20-NH-L y
m NaO ₃ S-4 0 ' i_ NaO ₃ S-- i. ir 15th * SO ψ L. SO 16.

ORIGINAL BATHROOM 109815/1625

NaO "S- "? ⁵

C = S

ι -NH

H N

C = S

NaO ₃ S- U. L ^ JH

CH,

C = S

ι -NH

f ^H 3

CH ₂ -CH ₂ -OH N _v ' ^V C = S

—.NH

C = S

3 " ^ p

HN _x ■ * -. ^ S ^ C = S

1 j; - NH

S = C

SO ₃ Na

NH

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25. SO_H H I ³ ^ j N— C = S

26th N.

-CONH- ^ K -C ^ ^V NH

SO ₃ H

₀ CC HO, S - ** ~ V-NH - NC = S

²⁸ SO-Na H

- I ³ Λ,

<f ~~~ X. -CH = N-NH-C NH NC = S

NaO ₀ S- ^ * V ^ C ^ NH L Ί— NC = S

³⁰ '- SO ₃ H

O'

HC-C C = S

H ₃ C

31 ^H.

^ N

H ₀ CC N-

³ H j HCC C = S

³ V

H ³² • H Cl

109815 ^ 1-625

177245ΐ

33 “H SO-Na
, N. | ³

³ ii ι ~ ■■ <■

H ■■■■■: ■■

The compounds to be used according to the invention are suitable not only for incorporation in stabilization solutions, in which they are easily soluble · They are also particularly suitable for settling in at least one of the colloid layers of the photographic material to be incorporated, preferably into the silver halide emulsion layer · The reason is that they are incorporated therein in the desired concentration leave without a noticeable desensitization of the photographic Material to cause what is probably the case how has already been discussed above - with most of the known heterocyclic mercapto compounds which are not solubilizing Contain sulfo groups. It also ensures the high Water solubility a homogeneous distribution of the invention en compounds in the casting composition of the layer, in which you want to store them. Because the inventive Compounds with the remaining silver halide to form soluble silver complexes are highlighted in the image Caused less staining with aging, because some of the silver complexes from the material in the stabilizing solution overdiffused. In addition, the concentration of the im Material with the compounds used according to the invention The soluble silver complexes formed are reduced by a post-stabilization consisting of a short soak will.

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The amount of compounds to be used according to the above general formula can vary within wide limits and depends on the nature of the individual compound and of the photographic Material for which they are intended. The optimal amount can be easily determined for each material by simple experiments. In general, these compounds are used in Stabilizing bath in amounts from about 0.1 g to about 10 g, preferably from about 0.5 to 5 g per liter of composition, fc and in the photographic material in amounts from about 10 mg to about 2 g, preferably from about 50 mg up to about 0.5 g per mole of silver halide is used.

The photographic emulsions can be of any type, e.g., they may or may not be spectrally sensitized be sensitized, and various silver salts can be used as photosensitive salts, e.g. silver bromide, Silver iodide, silver chloride or mixed silver halides such as silver chlorobromide, silver bromide iodide and silver chlorobromide iodide.

The silver halides are found in the usual hydrophilic colloids, e.g. gelatine, casein, polyvinyl alcohol, carboxymethyl cellulose, Alginic acid, etc., but gelatin is preferred.

The light-sensitive emulsions can be sensitized both chemically and optically. You can be chemically sensitized by preventing ripening in the presence of small amounts of sulfur-containing compounds such as allylthio-

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cyanate, allyl thiourea, sodium thiosulphate etc .. take place leaves. The emulsions can also use reducing agents be sensitized, e.g. tin compounds as described in French patent specification 1 146 955 and in US Pat Belgian patent 568,687, iminoaminomethanesulphinic acid compounds as described in British Patent 789,823, and small amounts of noble metal compounds such as of gold, piatina, palladium, iridium, ruthenium and rhodium. The light-sensitive emulsions can also be added Be sensitized by development accelerators, e.g. the compounds of the polyoxyalkylene type, such as alkylene oxide condensation products as described, inter alia, in American Patents 2,531,832 and 2,533,990, in U.S. Pat British patents ip20 637, 940 051, 945 340 and 991 608, and in Belgian patent specification 648 710, and of onium derivatives of amino-N-oxides, as described in "der laid-open Dutch patent application 6612269.

The photosensitive emulsions can also be one or more Developer substances such as hydroquinone, l-phenyl-3-pyrazolidinone, p-aminophenol and p-phenylenediamine derivatives, etc., antioxidants for these developing substances such as potassium metabisulfite, matting agents, etc. contain.

As has already been said, it is preferred at least a part and preferably even all of the developer substance or substances into the light-sensitive Incorporate material. That way the developer can

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be limited to a mere aqueous alkaline activation bath, thanks to the absence of developer substances has a longer shelf life

The following examples illustrate the invention.

example 1

A silver chlorobromide gelatin emulsion (60 mol % AgBr and 40 mol % AgCl) containing both hydroquinone and potassium metabisulphite as well as other common emulsion additives such as sensitizing dyes, hardeners and casting additives is cast on a conventional film support and dried.

The photographic material obtained is exposed to light and developed, for example in a developing bath at a rate per liter Contains 60 σ sodium hydroxide, 40 g anhydrous sodium sulfite, 2 g potassium bromide and 1 g l-phenyl-3-pyrazolidinone.

The exposed and developed material is then treated in a stabilizing bath with the following composition: Ammonium thiocyanate 250 g

Potassium metabisulphite 145 g

30% aqueous formaldehyde solution 120 ml 60 % ± ge aqueous acetic acid solution 25 ml compound 22 Ig.

Water up to 1000 ml

After drying, the image treated with the above composition is well stable against fading of the image silver and coloring of the highlights. Indeed, after a storage time of 18 days in an atmosphere at 20 ⁰ C and 60 % relative

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Humidity, or after 1 month of direct daylight the blackening of the image is less faded than that of an image made with a similar one Composition was treated, but did not contain a compound according to the invention, and the highlights are also less stained.

The same favorable results are obtained by using the Compound 22 by an equal amount of one of the compounds 2, 5, 7, 16, or 26 of the list above.

Example 2

0.1 g of compound 15 is added per mole of silver halide to a silver chlorobromide gelatin emulsion (60 mol% AgBr and 40 mol % AgCl), which contains both hydroquinone and potassium metabisulphite and other common emulsion additives such as sensitizing dyes, hardeners and casting additives. This emulsion is then poured onto a barite-coated paper base in a conventional manner and dried.

The material obtained is exposed and developed, e.g. in a developing bath containing 40 g of sodium hydroxide per liter, 40 g of anhydrous sodium sulfite, 2 g of potassium bromide and 1 g Contains l-phenyl-3-pyrazolidinone.

The exposed and developed material is then treated in a stabilizing bath as described in Example 1, which but does not contain compound 22

After drying, the image is compared to a material which does not contain a compound according to the invention, on storage of which the image silver is well stable and prevents fading of the image silver the coloring of the highlights.

Claims (5)

Claims 1. A method for producing photographic images, according to which a photographic material with at least one light-sensitive silver halide emulsion layer is exposed, the exposed material is developed, and the Material is treated with a stabilizing composition, eliminating the remaining unexposed silver halide is converted into a non-photosensitive compound, characterized in that this treatment in the presence of at least one heterocyclic thioxo compound is made, the thioxothiol tautomerism and corresponds to the following general formula: '-C = S in the Z the necessary atoms to close a 5- or 6-membered heterocyclic ring or a heterocyclic ring fused with an aromatic ring system presents, wherein the heterocyclic compound in its molecule has at least one sulfo group in acidic or salt form having. 2. The method according to claim 1, characterized in that Z represents the atoms necessary to close a benzoxazoline, a benzthiazoline, a benzimidazoline, a naphthimidazoline, a naphthoxazoline, a naphthothiazoline, a diazoline, a triazoline, a thiadiazine, a benzothiazoletriazine, a pyridine, a pyrimidine, a pyridazine, or a 109815/1625 - is- Triazine ring presents, all of which can be substituted. 3. The method according to any one of claims 1-2, characterized in that the heterocyclic compound is present in the treatment composition. 4. The method according to claim 3, characterized in that the heterocyclic compound in an amount of about 0.1g to about 10 grams per liter of composition. 5. The method according to any one of claims 1-2, characterized in that that the heterocyclic compound is present in at least one of the colloid layers of the photographic material is present. ο The method according to claim 5, characterized in that the heterocyclic compound in the photosensitive silver halide emulsion layer is present. ο Method according to one of Claims 5-6, characterized in that that the compound is in an amount from about 10 mg to about 2 g per mole of silver halide is present. 8ο Method according to one of the preceding claims, characterized characterized in that the stabilizing composition contains ammonium thiocyanate. · 109815/1625