chapter  9
24 Pages

Miscellaneous Uses of Plant Exudates

Africa) that are thought to date back to between 350,000 and 400,000 years (BBC News, 2000). About 30,000 years ago, cave paintings were created by cave dwellers as decoration. ese ancient paints were reportedly based on animal fat (binder) and colored earth or other natural pigments (ochre, for example). e binder provides adhesion, integrity, and toughness to the dry paint film by binding the pigment together. e binder also affects application properties such as flow, leveling and film build, and gloss development. e liquid portion of the paint makes it possible to apply the pigment and binder to a surface. Pigments and binder are what are left on the surface when the paint dries and the liquid portion evaporates. Together, these are called the solid portion of the paint. Paint with higher solids content will provide a thicker dry paint film for a given square-footage per gallon, which results in better coverage and durability compared to paint with lower solids contents. e oldest record of decorative painting can be traced to southern France. Gum arabic and gum tragacanth are beneficial in the field of artistic and historical works (Mills and White, 1994). ey have been applied since the 2nd century B.C. as binding media for pigments in Egyptian ointments used for mummification, in mural paintings in Christian catacombs (Schramm, 1988; Mills and White, 1994), in paintings on silk (Schramm, 1988), and in manuscript illumination in the Middle Ages (Doerner, 1989; Mills and White, 1994).