PIGMENTS FOR DECORATION In the manufacture of pigments, there are two actions, one chemical and the other mechani cal; and there is a great difference between the two. In a chemical compound a substance is produced which differs from the several ingre dients of which it is composed. A mechanical mixture, on the other hand, if put under a power ful microscope, reveals the fact that the atoms composing it are either unchanged or have altered merely in their shape, thus reflecting light in a different way.
The general qualities of good pigments are: beauty of color, purity, brightness, and depth of color; body; transparency; ease of manipulation; and durability. They should also keep their place, and dry or solidify well. Body in opaque pigments is the quality of coloring well; in trans parent colors it means depth, richness of color, or tinting power. Working well depends on either sufficient grinding, or fineness of texture, or the quality of the pigment. Keeping their place and drying well depend upon the liquid the colors are mixed with.
its name suggests, is a pigment of a blue hue of black. Its source is a charcoal obtained from the vine and other plants, cork cuttings, and nutshells; and its blue tone results from the thorough burning and levigation (making smooth by grinding) it goes through, as well as being due to the wood used in the first instance. It is very serviceable as a water-color pigment, and is indispensable to distemper work generally, being used extensively as a graining color. It produces soft grey shadows in some kinds of light woods; it also makes a fine neutral green with yellow, as its blue tone is useful for making low tones of green. It is very perma nent, and acts best as a water-color black. Al though not much used as an oil stainer, it is, nevertheless, useful and reliable as such.
- Ivory Black is at once the purest and blackest of all black pigments. Its name is derived from the supposition that it is—or was at one time— produced from burning ivory. The ordinary ivory black, however, is prepared by charring bones in closed vessels by a very strong heat. It
is most often termed drop black, and this by rea son of its being usually sold in the form of drops, or knobs, when in its dry state. It is not very successful as a water-color, but is a strong stainer in either oil or water. It is permanent in oil, and is most invaluable ground in turpen tine for producing flat or dead black paint for various purposes, and mixes well with other pigments.
is, as its name implies, carbon given by the soot from resinous or oily flames, and is obtained for commercial purposes from factories where the preparation of turpentine and tar is carried on. It is a good black, but not so intense as "ivory," being more of the color of India ink. It is very useful in either oil or water, and is quite permanent. It mixes well with most other pigments, but is spoilt if mixed with Prussian blue or Vandyke brown. It does not dry well.
as usually so termed, is a prepa ration of common blacks, but is ground in linseed oil to the form of a thick paste—very useful for common painting.
Vegetable Black is an article similar to lamp black, and obtained by burning vegetable mat ter. It is wonderfully light, and therefore rather troublesome to mix and handle.
is a form of native pigment we all are familiar with, but, notwithstanding it pos sesses certain estimable qualities of permanence and purity, it is seldom looked upon as a painter's pigment.
is a preparation very similar both in source and qualities to Prussian blue; used as an oil glaze, it is somewhat brighter and greener, but it is neither so intense nor so per manent as the latter, either in oil or water.
is a pigment seldom used by house painters, owing to its costliness. It is sec ond only to genuine ultramarine for beauty and purity of color, and is much favored for using as a sky blue, both in oil and water painting. It is not, however, nearly so strong a stainer as Prus sian blue, but is thoroughly permanent and reliable in oil and water.