Re: Resinotype: Melting rosin + pigment mixture -> question
can't we just dissolve the rosin in alcohol, add the pigment, grind and then wait for the - irrelevant - alcohol evaporates?Yes and (many) no... I tried this and I had a mixture remaining soft for years. One can solve this problem covering a glass plate with a thin layer of alcoholic mixture, then scratching it when it is hard enough (weeks, sometimes months...). Hence, I don't recommend it. An alternative method is to finely disperse the pigment in a solution of rosin in the minimum amout of caustic soda. Then dilute it (more or less for 50 g of rosin, 1 to 2 l of water) and add some chloridric acid while constantly stirring, until the solution turns acidic. The abietic acid precipitates, inglobing the particles of pigment. Filter, dry, then crush the aggregate. Alberto
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