Gilding refers to overlaying a metallic surface made from wood, stone, cloth, clay or canvas with a thin covering of gold -- but you can also apply silver or bronze gilds. Many paints are made in a similar way to a gild, where metal is added to a medium base to produce a strong color and a metallic luster. However, gold, silver and bronze are only sparingly used in paint; the more widely used metals are chromium, titanium, cadmium, aluminum and manganese.
Painters may also use paints that contain earth elements or minerals. Instead of a shiny gold color, a paint may be a deep brown or clay color and only contain minerals or elements such as iron, mica, cobalt, azurite, zinc or cobalt. In general, a painter, even an oil painter, will use various pigments in his paints, while the gilder or gold leaf artist deals mostly with gold.
The term "patina" describes how the surface of a bronze, brass or silver gilded item oxidizes over time. With this chemical change comes a tarnished look that is sometimes very desirable. Pure gold leaf will not tarnish, but sometimes when gilders or gold leaf artists want a slightly tarnished effect, they add a special substance to get this result. In general, painters do not deal with the patina effect.
"Gild the lily" is a phrase that means to overdecorate something when it is not necessary because the item is beautiful in its own right. It applies to gilding but seldom to painting. This underscores the reality that gilding is frequently used to decorate, but rarely is it applied to a painting in a manner that helps define the image. Although extremely beautiful, when done correctly, gold leaf is seldom used on the canvas. Usually, gold leaf artists use the paintlike material to create a stunning frame for the picture.