Preparing the Paint.
Such being the principal materials from which the painter prepares his paint, we proceed to speak of the mode by which he mixes them. The colours are mostly purchased in that form which is called dry colours, that is, in coarse powder or small lumps; and they have to be reduced to fine powder before they are mixed with the oils, &c. If they contain gritty particles of sand, &c., the colour is put into a tub or pan, and water thrown upon it, and mixed up with it. The gritty particles soon fall to the bottom, and the remainder is poured into another vessel, where, in a short time, the colouring substance falls to the bottom, and can be obtained by pouring off the water; after which the powder is dried. But if the substance is one which will dissolve in water, or if it is not very gritty, it is ground up to powder in a dry state.
When the substance is reduced to fine powder, the painter begins to incorporate the oil with it. He has a grindstone of marble or porphyry, on which he places a small quantity of the dry colour, and moistens it with a little oil. With a large flattened pebble, called a muller, he then grinds up the powder with the oil, until both form a perfectly smooth paste. That portion is then removed by a palette knife, (which is a broad thin knife,) and placed in an earthen paint-pot. Another small portion of powder and oil is ground up in a similar manner, and put into the paint-pot; and so on, until a sufficient quantity has been obtained. When this is done, the pot contains paint, which is too thick for use; to liquefy it, therefore, a given quantity, which is determined by experience, of oil or turpentine, or a mixture of both, is added, until the paint has acquired a consistence—thick enough to prevent it from running into drops when laid on the work—and thin enough to make it work with ease.