Wednesday, 1 October 2008

Paints and Stains

Vitreous paint - glass paint which contains finely ground lead or copper filings, ground glass, gum arabic and a medium such as water, oil, wine, vinegar or urine. These are either high-fire blacks and browns or low-fire transparent colours.

Silver stains - silver nitrate and gamboge gum that chemically stain the glass to varying intensities from pale yellow to orange.

Gamboge is a rather transparent dark mustard yellow pigment. Gamboge is most often extracted by tapping from the Garcinia hanburyi tree. The resin is extracted by making spiral incisions in the bark, and by breaking off leaves and shoots and letting the milky yellow resinous gum drip out. The resulting latex is collected in hollow bamboo. After the latex is congealed, the bamboo is broken away and large rods of raw gamboge remain.