Varnishing An Oil Painting

Varnish is more than simply a layer to protect your oil painting from ultraviolet light, pollution in the atmosphere and abrasion. It will also bring out the brilliance in colors, making them sparkle. Varnish is made from Damar resin dissolved in a mixture of turpentine and other organic solvents. Keep in mind that oil paint dries from the outside in; when it dries, it forms a surface skin first. During the drying process small pores form in this surface skin. The surface of the paint may feel dry, but under the skin, the paint is still wet, no matter how thin the coating is. It takes at least 6 months drying time for the dried oil paint film to become dry enough that it won’t be re-dissolved by mild solvents such as turpentine. When a varnish is applied to a reproduction art oil-on-canvas painting before the 6 month drying time, the varnish fills the pores of the oil paint film, The solvent content of the varnish can easily re-dissolve the incompletely dried oil paint at the bottom of the canvas and cause all kinds of problems – such as wrinkling of the oil paint film, cracking, and yellowing of the color.