The word icon comes from the Greek word eikon, meaning image. Often referred to as "theology in color" and "doorways to heaven," icons are a form of sacred art, the content of which is spiritual. Iconographers paint, or "write," icons as a visual way of expressing faith. Iconographers incorporate symbols within icons, creating images of restored or renewed creation—transfigured existence made possible through life in Jesus Christ. The images are not meant to be only naturalistic representations, but also "spiritual" portraits where the symbols lead you through the subject's faith story. Thus an iconographer is more a minister than an artisan and an icon more a sacramental than a work of art.
Byzantine-style icons are usually painted on icon boards, made of hardwood or plywood which is covered with a thin layer of fine linen cloth. Up to 15 layers of gesso primer is applied to the linen board, each coat sanded smooth before the next is layed down. This creates a very smooth and absorbent surface on which thin coats of paint are painted in numerous layers.
After the icon's image is sketched or engraved onto the gesso, the iconographer begins by painting base coats of all the dark areas of the icon. Then slowly lighter and lighter areas are added until the icon is complete. This process reflects the spiritual life—a movement from darkness into the light of Christ. Details and highlights that complete the icon are added last.
Gilding with gold leaf is frequently used in iconography as a symbol of divine light radiating from transfigured humanity. Indeed, there is no exterior light source within an icon, the light comes from within the figure, depicting the Christian truth that the light of Christ is an interior light within believers.