It is a natural product that increases the gloss and transparency of watercolours.
Gum arabic is used as a binder for watercolour painting because it dissolves easily in water. Pigment of any colour is suspended within the acacia gum in varying amounts, resulting in watercolour paint. Water acts as a vehicle or a diluent to thin the watercolour paint and helps to transfer the paint to a surface such as paper. When all moisture evaporates, the acacia gum typically does not bind the pigment to the paper surface, but is totally absorbed by deeper layers