Casein paint (a derivative of casein protein), is a water-soluble, fast-drying medium used extensively by painters for modeling. The paint itself is made up of two primary components, including glycerol (an albumenoid) and pectin. Glycerol provides the characteristic yellow color and viscosity of the paint while Pectin supplies the flexibility and resilience of the paint’s texture. For this reason, it is widely used in preparing acrylic paints for use in decorative crafts.
Artists often use casein paint for blending and adding shading to acrylic paints. It is also used on many canvas paintings to create subtle highlights. However, its drying time is much slower than that of oil paints and it can be used on almost any surface. The medium is most popular for painting flat surfaces because it dries very fast and gives a stiff, matte finish. For this reason, casein paint is most often used on canvas as part of the final drying process.
The Masonite (aluminized aluminum clay) used in the production of acrylics is extracted from pine trees. This preparation requires extremely high temperatures and is labor intensive. Not only is Masonite slow to dry, but it stains easily and bleeds when exposed to moisture. As a result, most acrylic paints contain Masonite to improve their resistance to staining and fading. Today, casein paints are frequently used to make acrylics suitable for interior use.
Because Masonite is a water-soluble medium, its drying time is much less than that of oil paints and it dries fairly rapidly, allowing artists to complete their work without waiting for an overnight wash. Other characteristics of casein painting include its fine texture and consistent coverage. As a result, the paint can be applied over a wide variety of media including watercolor, pastels, and charcoal.
The pigment, or casein, itself is not a solid mass, but is actually a gelatinous mass of amino acids. It is suspended in a liquid medium called gesso or a gel. The term lesson is derived from the Italian word that means “to put together” and refers to the fact that the mixing of the casein and less is done to achieve a smooth, thin, creamy appearance. Although the mixture does not contain any fats or oils, it is considered to be a water-based medium. Gesso-based casein paints are popular with artists who prefer to work on a large canvas rather than a small, table-top model. Another advantage of casein-based painting medium is that the process of drying is relatively fast and inexpensive.
Gesso or watercolor paint is available in two basic forms, liquid and semi-viscous. They are often combined with other mediums, such as oil, to create more complex hues and shades. Because of their water solubility, they are frequently used for blending effects on thin paintings, like watercolor paintings. They are also commonly used as the base paint for all types of mass-produced paintings, most commonly representing cosmetics. Gesso and watercolors are still being developed; however, they are becoming more widely accepted as an alternative to oil, especially for fine arts.