Origin of Paints
Origin and Sources of Paints
The mineral kingdom yields the great bulk of pigments used in plain and decorative house-painting. Native paints are found, in certain geological formations, in inexhaustible and boundless supply.
These are generally neutral tints or shades, being mostly silica colored with iron oxides. They are useful and durable both in color and substance, and as a rule are not as liable to change as are the colors produced by chemical agency.
The animal kingdom furnishes the bright scarlet known as carmine, and crimson and purple lakes, as also Prussian and Antwerp blues. Colors extracted from vegetable substances have been mostly discarded in painting, by reason of their fugitive character. Among those retained are the madder-colors, indigo, and gamboge.
History of Painting
The important pigment lampblack is also classed among vegetable colors. All the metals yield pigments of some sort. Lead yields white-lead, and other whites of similar nature and composition, distinguished by various names, as silver-white, Krem’s white, China white, etc. ; also orange mineral, red oxide, called red-lead, and the gray oxide, called litharge.
Zinc furnishes the beautiful paint known as zinc-white. Copper gives verdigris, and, in combination with arsenic, the unrivaled green known as Paris or emerald green—for a comprehensive and detailed description of which see Chapter XI, entitled ” Paris Green as a Pigment.” Iron furnishes Indian red, Mars brown, Mars orange and yellow, and Venetian red.
Mercury produces in combination with sulphur what is known as true vermilion. Arsenicum supplies King’s yellow and orpiment. Cobalt blue and smalt are made from the metal cobalt, and the recently found metals, such as uranium, cadmium, molybdenum, etc., produce colors of peculiar beauty and brilliancy. White lead, the comprehensive term for white pigments, for ages the only substance which includes all the qualities or properties required by the painter, is an oxide of that familiar metal, lead, more popularly known, perhaps, than any except iron.
The metal, liquefied by heat, is run into molds forming a circle or ring, with bars across something like a round gridiron ; the object being to present as much surface as possible, conformable to certain other requirements.
These shapes buckles, as they are technically called are exposed some weeks, more or less, in covered earthen pots, to the action of vinegar, or other acetic acid, volatilized by gentle heat.
Through the action of this vaporized acid, the metal gradually loses its metallic structure and character, and takes on the appearance of a whitish, friable substance, which is chemically known as carbonate of lead. This, after being washed and crushed, and ground in oil, is the white-lead paint of the painter.
The other white pigment (white oxide of zinc) is produced as follows : The ores, crushed to the size of coarse sand, and mixed with fine coal, are spread on the fire, and, when raised to 2,000° Fahrenheit, are de oxidized ; the oxygen of the ore uniting with the coal, forming carbonic acid gas, the zinc rising as a metallic vapor.
The vapor and gases are sucked from the furnace, and conveyed through iron pipes to a large room into which they are driven, and out of which the gas escapes. This room is filled with large, stout bags, suspended open-mouthed to catch the zinc, which, in its passage from the furnace to the bags, goes through chambers into which air is admitted.
In its vaporous form it unites with the oxygen of the atmosphere, forming the light, flaky substance known as flowers of zinc. The oxide at this stage is extremely light, thirty or forty pounds being sufficient to fill a barrel. It is then compressed to about one fourth of its former bulk, and packed in barrels of two hundred pounds or casks of four hundred pounds, and sold to manufacturers whose business it is to prepare the same, by mixing and grinding in oil, for the use of the painter. Lampblack, drop-black, ivory-black, bone-black, Frank-fort black, are the names applied to the simple substance which affords all the blacks used in painting, and in the manufacture of printer’s ink, viz., carbon.
Lampblack, the most important and, useful form of carbon to be considered here, is produced from the article known in trade as common rosin, or other bituminous substances. The finer kinds are made from rosin, and the common kinds from coal or gas tar. All resinous, oily, fatty substances produce lamp-black in the process of burning it being simply the soot resulting from highly combustible bodies as they are imperfectly consumed.
Origin and Sources of Paints Article Source : This article courtesy should goes to House Painting Carriage Painting and Graining by John W Masury.