The composition of paint
Paint (read here also pastel or ink) is generally made from colour-imparting substances and binders. Extenders, solvents and additives may also be incorporated in paint.
Some binders may be in liquid form, while others are solids and have to be dissolved or mixed with a solvent (for example water or white spirit) in order to obtain a liquid binder. Solvents evaporate from the paint during the drying process.
Certain colour-imparting substances dissolve in the liquid binder of the paint or in the solvent that gives the binder its liquid form. These substances are called dyes. Colour-imparting substances that do not dissolve are referred to as pigments.
Extenders are used, for example, to partly replace the pigment if the tinting strength of the pigment is too high, or to replace a certain percentage of the (often very expensive) pigments with a less expensive extender. This, however, does not reduce the durability of the paint layer.
We understand additives to mean any substances that are added to improve the stability or ease of use. These can include siccatives (drying accelerators), preservatives, fluidifying agents and thickening agents.