GB210862A - A new or improved light sensitive film or layer and process for making same - Google Patents

Abstract

210,862. Sokal, S., (Kalle & Co., Akt.- Ges.). Nov. 7, 1922. Plates, films, and papers.-Diazo-anhydrides formed with the separation of water from oxydiazo compounds or from indazol diazo-hydroxide are used as light sensitive layers. Amino salicylic acid or its anhydride are excluded from the scope of the invention. The sulphonic acids of the anhydrides of 1-diazo-2-naphthol or 2-diazo- 1-naphthol or their halogen, nitro, or other derivatives, bisdiazo-p-diphenol, or indazoltriazolen are chiefly used. The yellow diazo compound bleaches and is destroyed on exposure to light. A positive can be produced from a positive (1) by coupling up the unexposed portion with an azo-colour component in the presence of alkali either by subsequent treatment in a bath containing the component and alkali, or by incorporating the component in the sensitive layer with the addition of tartaric citric or like acids to increase stability and coupling after exposure by treatment with ammonia fumes or alkali solution (2) by exposing the whole layer for a short time to light after exposing under a positive, so that the previously unexposed portion is partly decomposed forming an azo colour component which can be coupled up with the still undecomposed portion by treatment with alkali, or by storing for some time in the dark, to give a picture. A positive may be obtained from a negative by adding an alkali or acetate to the sensitive layer, a picture being immediately produced on exposure; the unexposed portion of the layer is then washed away. A mordant, such as tartar emtic, may be added to the layer. The picture produced may be coloured by means of bichromate, and like oxidizing agents. Metal salts, particularly of copper, nickel, iron, manganese, mercury, zinc, and aluminium, may be added to the layer, or to its carrier or to the developing bath, to make the picture fast to water and to produce different shades and colours. Resorcinol, phloroglucinol, or phenylmethylpyrazolone may be used as azo colour components. Specifications 20073/11 and 20073/11, [both in Class 2 (iii), Dyes &c.], are referred to.