Painting technique in which the pigment is bonded with an extremely durable film of glassy silicates or silica. The end result can resemble either buon fresco or fresco a secco, depending on the exact method and choice of materials. The technique was apparently invented by alchemist Basilius Valentinus in the 15th century. It was rediscovered ca. 1818, and commercial paints were available until the 1960s in Germany. Silicon esters, in particular ethyl silicate, replaced water glass in modern silicate paints.