Universal Black Reusche Paint is a vitreous paint that is a mixture of ground glass and a pigment oxide. These superior, traditional glass stainer colors from Reusche are the same type of stains used in the centuries old art of traditional glass painting. All colors are mixable to expand your palette and suit your purpose. These stains are typically mixed with water and gum arabic or other mixing agents before applying to glass and kiln firing. These colors mature at a firing temperature of 1200 F - 1250 F. and cure to a medium gloss opaque. Sold in 1 oz. package - 1 oz. covers approximately 300 sq.in. Please Note: these colors are not approved for food-bearing surfaces.