| 摘要 |
306,408. Kalle & Co. Akt.-Ges. Feb. 16, 1928, [Convention date] Diazotype sensitive layers, which may include an azo coupling component, and may be developed with alkaline gases, as described in Specification 234,818, are stabilized by the addition of compounds containing bivalent sulphur, especially derivatives of thiocarbonic acid, such as thiourea, thiosinamine, thiocarbamic acid and derivatives thereof. Thio-glycollic acids may be used, and colloidal sulphur also produces an effect. The layers may also include acids, metallic salts, and colloidal-bodies such as gelatin or dextrin. Examples are described in which thiourea is added to layers containing (1) 2-1-diazohydroxynaphthalene-4-sulphonic acid, phloroglucine, and titanium ammonium fluoride; (2) the double salt of zinc chloride and the diazo-compound of 2- aimino-5-ethylamino-1-toluene, phloroglucine, boric acid, tartaric acid, and aluminium sulphate; and (3) the diazo-compound of 1-dimethylamino-4- ammo-3-methylbenzene, phloroglucine, resorcin, borax, tartaric acid, aluminium sulphate and dextrin. Development with alkaline vapour may be followed by a short treatment in a moist warm atmosphere.
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