Varnishes

are made by di olving resins or gum-resins in alcohol, ether, ., so that as the spirit evaporates the varnish dries down into a transparent film; varnishes are coloured with aloes, an not to, cochineal, dragon’s blood, gamboge, indigo, red saunders, saffron, or turmeric. Amber varnish is hardest and most durable in colour, but dries very slowly. Animé varnish dries quickly, but is liable to crack, and deepens in colour with exposure to the air. Copal ranks next to amber in durability, and the varnish becomes lighter by exposure; the best copal varnishes are slow in drying unle mixed with animé. Mastic is a favourite spirit varnish used as a picture varnish and for delicate works of a pale colour. Damar mixed with mastic makes an appropriate varnish for maps and similar work. The qualities to be sought in varnishes for a painting are that they should resist damp, exclude air, and not injure the colour. (See also Italian varnish, Strasburg turpentine, .)