GB1312809A - Diazotype photogrpahic materials - Google Patents

Abstract

1312809 Diazotype materials containing ultraviolet absorbers EASTMAN KODAK CO 16 July 1970 [18 July 1969] 34524/70 Heading G2C A two-component diazotype material comprises a support coated on the same or opposite sides with at least two layers containing a diazonium salt and a coupler; the support being transparent if coated on opposite sides, the material also containing a layer having an alkalibleachable ultra-violet absorber, this layer being between the support and the first diazotype layer so that the effective speed of the second diazotype layer is reduced to a value less-than the first layer when exposed from the side of the first layer. The preferred materials all contain two diazotype layers with the u. v. absorber being (i) in a layer between the two layers or in the lower layer when the two layers are coated on the same side of the support or (ii) coated on the support below a diazotype layer when the diazotype layers are coated on opposite sides. Preferred diazotype layers are those of specification 1231270 and containing a binder such as a vinyl or acrylic polymer, a polyester or a cellulose ether or ester. Preferred u.v. absorbers are thiapyrilium and pyrilium salts of formula wherein D is oxygen or sulphur, T, is alkyl, alkoxy, aryl or substituted aryl and T 2 is hydrogen or a group defined under T 1 .