A contemporary iconographer speaking:

“To produce a good icon, the icon-painter must adhere to ancient techniques.  In old times, the traditional background for icons was gold leaf or silver leaf. Gold being expensive, icon-painters often used simple paints that were cheap and made of natural ingredients. In the poor village churches of Russian North, all the backgrounds were done with paints of very light color. ‘Fon,’ the Russian for background, is not a Russian word. Our icon-painters called it ‘the light’. Priming for the panel was made of sturgeon glue, also a very expensive material. Well, in old times icons were not cheap… “ (Father Zinon)

Icons are religious images painted on wooden panels, typically made of linden or pine wood. Their production is a long and complex process. A layer of linen cloth soaked in sturgeon glue is put on the panel. The ground is made of chalk mixed with fish glue. This is gesso. Up to ten layers of the gesso are applied over the cloth, or pavoloka . An outline of the composition is incised on the gesso with the point of a needle, often based on an icon-painting manual.

To prepare tempera paints, mineral pigments are mixed with water and egg yolk. The common minerals are cinnabar for reds, ochre (iron oxide) for yellows and lapis-lazuli for blues. Natural minerals give transparency to colors. Transparency is key in creating the effect of luminosity in icons.  Light and dark tones of different thickness are brought one on top of the other, layer after layer.  The white ground reflects light falling on its surface back through the semi-transparent tempera. The effect is that of inner light radiating from the image.

After painting is done an icon is varnished with boiled linseed oil, olifa. Russian artists added amber to their olifa. The linseed-amber varnish protects icons from scratches and gives them a deeper tone. But, after many years in a wood-heated church or in a candle-lit ‘red’ corner of a peasant hut, the varnish becomes very dark and obscures the image. In the early twentieth century, to clean the old varnish off the icon surface, restorers used fire to soften the olifa. They put a little alcohol on the surface of an icon and set it on fire. A restorer then was able to scrape off the olifa varnish and clean the icon.