GLASS PAINTING

In Painting. The method of staining gla in such a manner as to produce the effect of representing all the subjects whereof the art is susceptible. A French painter of Marseilles is said to have been the first who instructed the Italians In this art, during the pontificate of Julius II. It was, however, practised to a considerable extent by Lucas of Leyden, and Albert Durer. The different colours are prepared as follows: Black is composed of two thirds of iron scales or flakes, and the other third of small gla beads, or a substance called roccaglia by the Italians. White is prepared from sand, or small white pebbles, calcined, pounded, and then ground finely; one fourth part of saltpetre is added, and the mixture is then again calcined and pulverized: when dyed, a little gypsum or plaster of Paris is added. Yellow is formed from leaf silver ground and mixed in a crucible with saltpetre or sulphur; then ground on a porphyry stone; and, lastly, ground over again with nine times the quantity of red ochre. Red, one of the most difficult of the colours to make, is prepared of litharge of silver and iron scales, gum Arabic, ferretta, gla beads, and bloodstone, in nearly equal quantities. Experience alone will command succe in making this colour. Green is formed from a:s ustum one ounce, the same quantity of black lead, and four ounces of white lead, incorporated by the action of fire. When calcined a fourth part of saltpetre is added, and after a second calcination a sixth part more; after which a third coction is made before using it. Jlzure, purple, and violet are prepared in a similar manner to green, omitting the res ustum, and in its stead using sulphur for azure, perigneux foi purple, and both these drugs for violet. Carnations are compounded colours, are calcined, and mostly mixed with water, and must be finished part by part, and each with great despatch, before the plaster dries, and there is little opportunity for blending. The lights cannot be heightened; but the shadows may, when they begin to dry, be a little strengthened. Promptitude and facility in execution are the great requisites for this method of painting. See Cartoon. [s. 534]