Decorative Papers
The traditional manner of marbling paper is often called "Turkish" marbling or ebru because it originated in the old Ottoman empire of the 15th century. Water-based inks containing ox gall (bile) as a dispersant are floated on the surface of water thickened with gum tragacanth or carragheenan moss (actually a seaweed). The colours are then drawn into patterns by means of sticks or combs, specially-prepared paper is laid gently on the surface, left for a few seconds, and just as gently removed, rinsed (to wash off dirty size or excess colour), and hung to dry. Papers used should be fairly hard-surfaced and treated with alum as a mordant to take the pigment and to improve colour tone and colour fastness.
Another traditional form of decorating paper is suminagashi, a Japanese method which apparently dates back to the 12th century, and which differs from the Turkish method in that the water is unthickened and the colours actually dye the paper (Japanese papers are usually softer and more absorbent), whereas in ebru the colour pigments become attached to the paper surface.
Another, newer, technique for marbling paper is called "Swedish" and uses oil-based paint on unthickened water, the paint being thinned and dispersed by means of a solvent such as turpentine. Less preparation is needed for this technique, but control over patterns is limited and the papers take longer to dry. The paper does not have to be treated, nor need it be rinsed.
Finally, a very simple method of decorating paper for bookbinding is paste marbling, which is reminiscent of finger painting. Coloured paste, made from flour and water (1:4) or other cold water paste and coloured with watercolour or tempera paint, is spread onto paper and patterns are drawn with fingers, sticks, combs, or anything else at hand. While the end result is often less vibrant than traditional marbling methods, some very handsome and intricate designs have been created.