Abstract: A diazotype material useful for making duplicates of continuous tone originals, such as X-ray films, comprising a transparent film support having a coating of a layer thereon consisting essentially of at least two light-sensitive diazo compounds having different photolysis rates, couplers for the diazo compounds, an ultraviolet radiation absorbing material and homogeneously distributed in the layer at least about 7% by weight, based on the weight of lacquer, of an inert particulate material such as silica. The use of this material makes it possible to approximate a logarithmic photolysis, thereby providing sufficient linearity in the corresponding characteristic curve to achieve the desired duplicating results.

Abstract: An acid donor sheet for use in thermographic imaging which comprises a substrate sheet material having a coating comprising an organic acid which is volatilizable at thermographic imaging temperatures, an additive consisting essentially of a fatty acid having from 10 to 26 carbon atoms or a metal salt thereof, and a polymeric binder compatible with said volatilizable acid. A preferred composition is salicylic acid, lauric acid and nitrocellulose on a polyester base. The acid donor sheet of the invention is particularly useful in providing color projection transparencies having improved image density, readability, and permanence.