Acrylic colors consist of a pigment ground in an acrylic resin that is polymerized and then dispersed in water. Acrylics dry very quickly by the process of evaporation. They only require water to be diluted and for cleanup.
Because acrylics contain water, they usually dry darker as the water evaporates. This shift in color value makes it difficult to match colors once they have dried. Manufacturers are making great strides in both reducing the amount of color shift and prolonging acrylic drying times. Both Golden Artist Colors and Chroma are now producing “open” acrylics that dry much slower, allowing the artist more time to blend and work the colors.
Acrylics have less pigment than traditional oils. Their main advantage is that they remain flexible after drying, unlike oils, which become brittle with age. Also, it is not necessary to follow the fat-over-lean principle when working with acrylics.
Acrylics are produced in a wide range of colors and types (viscosities) including fluid, light body, heavy body, extra-heavy body and slow-drying. These are available in tubes and jars in a variety of sizes.
The primary purpose of an acrylic medium is to increase the binder in the acrylic color. Additional uses for acrylic mediums are to change:
There are so many acrylic mediums on the market that it is beyond the scope of this book to cover them all. However, we will focus on the most widely used and commonly available mediums.
John D. Cogan enjoys the advantages of the longer drying time while working with open acrylic paints. He can achieve the look of an oil painting without having to adhere to the fat-over-lean rule. Open acrylics mix with traditional acrylic paints, but this will speed up the drying time.
Inspiration Point
John D. Cogan
Open acrylics on stretched canvas
24" × 36" (61cm × 91cm)