When thoroughly dry, a design is incised into the surface. Then painting is begun, using the incised outline as a guide. Tempera paints, powdered colors mixed with egg yolk and a small amount of rye beer, are applied in gradations of shade, with dark colors added first and lighter colors applied over them, resulting in a slightly three-dimensional effect. The finished icon is varnished with a boiled linseed oil mixture that brightens and protects the colors. Over time, however, it darkens and obscures the painting.
Some icons have gold leaf added to background, garments and halos.
Others have silvery metal leaf tinted to appear gold. Some use paint in place of gold leaf. Traditional icons made prior to the 17th Century are painted in a nonrealistic, stylized manner intended to reveal the spiritual nature of the figures depicted rather than accurate anatomical detail. Background hills and buildings are stylized as well. Everything is abstracted from reality to depict a transfigured, timeless world in which material laws of form and substance are transcended.