What Sort of Oil is used in Oil Paint?
Unlike tempera, acrylic paint, watercolor, or gouache, all of which dry by evaporation, oil paint dries by oxidation: meaning, the oil reacts chemically with oxygen in the air and gradually changes from a liquid to a gel and finally becomes hard.
What Types of Oils are used in Oil Paint?
The most popular type of oil used in oil painting is linseed oil because it dries by oxidation. Safflower, poppy seed, or walnut oil may also be used, depending on the sheen, drying time and other effects required by the painter. However, linseed oil tends to dry faster and forms a more flexible paint film that can be reworked more easily. Pigments do not dry at the same speed: charcoal black oil paint, for example, tends to be slower to dry while red/yellow ochre hardens much faster.
How is Oil Paint Made?
First comes the grinding of the pigment in oil. The oily paste is thoroughly milled to disperse the pigment color particles throughout the mixture. Then the thinner and perhaps an additional siccative, a drying agent, are added.
What are Extenders?
Painters have added extenders or fillers to their oil paints in order to make expensive pigments go further and thus reduce the cost of their artist materials. Nowadays, barium sulfate and alumina hydrate are common extenders, being considered as the white pigments. Adding either of them to oil paint, increases the quantity of paint without affecting color as neither has any significant tinting power.
What Are the Advantages of Oil Paint?
The main advantages of oil paints are their flexibility and depth of color. They can be applied in many different ways. Because it is slow to dry, artists can continue working the paint for much longer than other types of paint. This provides greater opportunity for blending and layering. Oils also allow the artist to create greater richness of color as well as a wide range of tonal transitions and shades. In fact oil colors do not change noticeably after drying, and it is possible to produce both opaque and transparent effects, as well as matt and gloss finishes.