DE1013168B - Process for improving the whiteness of color photographic images - Google Patents

Description

GERMAN

Those made by color development and other photographic processes Color images generally contain dyes or dye components, the phenolic ones Carry hydroxyl groups. So z. B. for color photographic materials after the Processes of color-forming development are processed, naphthol derivatives as dye components used for the cyan partial color image. These color images show the disadvantage that they can be used for longer Extension of the final watering form an unpleasant color haze, the hue of which is from pjj value of the water used for irrigation. As has been stated, this is based Color haze on the formation of colored complex compounds of the aforementioned phenol derivatives with Heavy metal compounds, especially iron compounds, which are used in the water to water the pictures Water are present in dissolved or suspended form. If the watering is used to generate The materials used for these color images are carried out with rust-containing water on contact with the ferricyanide potassium used to bleach the silver on the color images Form spots of Berlin blue.

It has now been found that these errors can be avoided or eliminated in the production of the color images leave if you have the pictures in the presence during or after the usual processing of those compounds which are able to form more stable complexes with iron ions than those for Structure of the color images used, dyes or dye components containing phenolic hydroxyl groups, treated. Suitable complexing agents are, for. B. the alkali salts of polymeric phosphoric acids and also organic acids or water-soluble salts of the organic acids of the general formulas

HOOC-R ₁ -XR ₂ COOH,

in which X denotes —C—, —O—, —S— or = N — R ₃ , where R ₁ , R ₂ and R _{3 represent} hydrocarbon radicals which in turn can be substituted again, and where R _{3 can} also represent H .

Compounds that come under this formula are, for example, citric acid, diglycolic acid, thiodiglycolic acid, also amino acids which contain more than one carboxyl group in the α-position, based on a basic nitrogen atom, such as. B. nitrilotriacetic acid, ethylenediaminetetraacetic acid. Of these compounds, the amino acids mentioned, in particular ethylenediaminetetraacetic acid, also the water-soluble salts of polymeric phosphoric acids are particularly effective in the process to improve the whiteness of color photographic images

Applicant:

Agfa Aktiengesellschaft

for photofabrication,

Leverkusen-Bayerwerk

Dr. Max Heilmann, Leverkusen-Wiesdorf,
has been named as the inventor

grasslands. Tartaric acid and its water-soluble salts have also proven useful.

With the help of these complexing agents, the color haze produced by iron compounds can be converted into remove the color images without attacking the image dyes. The complexing agents are applied in aqueous solution before or after the final rinse, they can also be added to the water used for the final rinse. It is also possible to share them with others Treatment baths, such as B. bleach baths, hardening baths, light protection baths, etc., or other treatment baths to combine.

The following examples serve to illustrate the invention.

example 1

A photographic color image on a paper substrate obtained by the process of color-forming development, the blue-green partial color image of which was obtained from a color component containing a phenolic hydroxyl group and in which a color haze formed during the final rinse in an iron-containing tap water, is 15 to 20 minutes in a neutral 20 % solution of sodium hexametaphosphate bathed, then rinsed briefly and dried. In the ^{picture treated in this way 1} , the color haze has been removed. Instead of the solution of sodium hexametaphosphate, a 10% solution of the sodium salt of nitrilotriacetic acid or a 20% solution of sodium nitrate can be used with the same success.

Example 2

A color photographic image of the type described in Example 1 in which, by using rusty wash water before bleaching blue

70Ϊ 590/306

Spots of Prussian blue are left for minutes in a 20% solution of the Sodium salt of ethylenediaminetetraacetic acid bathed. Here the bruises disappear completely, without the image dyes being attacked.

Claims (2)

Patent claims: 1. Process for improving the whiteness of color photographic images, the image dyes or contain paint components with phenolic hydroxyl groups, characterized in that that the images with the aqueous solution of a salt of a polymeric phosphoric acid or with the solution of a complex-forming organic carboxylic acid of the general formula HOOC-R ₁ -XR ₂ -COOH,
in which X denotes —C—, —O—, —S— or = N — R, where R ₁ , R ₂ and R _{3 represent} hydrocarbon radicals which in turn can be substituted again and where R _{3 can} also represent a hydrogen atom , or with a solution of tartaric acid or with a solution of a water-soluble salt of the acids mentioned, which are able to form more stable complexes with iron ions than the image dyes or dye components mentioned. 2. The method according to claim 1, characterized in that that the pictures with a solution of the ethylenediaminetetraacetic acid, the nitrilotriacetic acid or a water-soluble salt of these acids. Considered publications:
U.S. Patents Nos. 2,356,486, 2,483,971,
440 954, 2,475 134. © 70Ϊ 590/306 7.57