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Re: Rosinotypes without Rosin ?



Could you please remind us why it was that Rodolfo Namias decided to mix rosin with pigments rather than simply using just pigments.
Something to do with stabilizing the powder in the gelatine?
Using fixed out bromide paper, washed, dried and sensitized I have used only pigment powders brushed onto the swollen matrix with some success.
Pure pigments perhaps may work on photographic paper, but if you use them directly on gelatine you obtain a muddy print. The rosin (but nowadays we might use any other more modern hydrophobic substance) helps to differentiate the sticking of the powder to the (more) wet areas, where the gelatine has not been hardened by light+dichromate, and the (less) wet areas where the gelatine has been hardened. Rosin is simply one among the cheaper substances you can use.
Namias wrote that he had his idea because, working on a bromoil with an ink made too stiffen with rosin and pigment, he obtained a reversed image. In fact, this is also the matter of his patent.
Alberto