Turkish marbling is said to have begun in the 15th century to prevent the forgery of legal documents. Having prepared the paper, the scribe then wrote on top. It was virtually impossible to alter that document or produce a copy, since no two patterns were identical. Marbling is produced by floating water-based inks or pigments on top of a gelatinous surface, made when gum tragacanth or carrageenan is dissolved in water. The inks are moved around with picks or combs, then mordanted paper or fabric is laid on top to absorb the coloured pattern. Instructions are given for preparing all the necessary solutions and materials, then a step-by-step guide to carrying out marbling. U. S. suppliers of materials are listed.