How to Mix Oil Paints

HOW TO MIX OIL PAINTS To set down exactly the proportions of dif ferent pigments necessary for producing any desired tint or color, may at first sight appear an easy task. For instance, it may be said, "Mix together three parts of lead, two of black, and one of yellow," but the practical informa tion given is small. Apart from the fact that there are a great number of different browns, ideas vary considerably as to what is a brown; and this applies to every other color. If a dozen practical house-painters were asked to mix a maroon paint, it is almost certain that no two of them would be exactly alike, even though compounded from the same materials. When opinions differ so widely as to the exact tint or shade of a named color, to give proportions of materials with exactness in the above-men tioned formula has but indefinite value, because the kind of red is not mentioned; nor, indeed, is the kind of yellow, or of black.

Another and even more important reason makes it impossible to give exact proportions; and this is owing to the strength and quality of paints of different manufacture differing so largely. The pigments used by one maker may be strictly pure, while those used by another may contain fifty per cent of adulterant, and for that reason be only of half the full tinting strength; or they may be pure, and yet be de ficient in tinting strength. Hence it will be seen that even with a sample color to work to, the results would differ unless materials were used of exactly the same quality in each case.

Although it is not possible to give propor tions of materials in figures, it is possible to give some idea of the amount of each color that should be used; and in making out the list which follows, the proportions in each case are indi cated as closely as it is safe to go. It is sup posed that pigments of first quality are used; and the reader must be warned that if inferior pigments are employed the tints produced by the admixture of them will always be more or less unsatisfactory, having, as a rule, a muddy cast that is very objectionable.

A word may be said as to the names of colors used in the following list :—It would be an easy matter to make the list ten times longer than it is by including all the names of colors that are used in the arts, especially those employed by the manufacturers of textiles.

And names of pigments are not always sy nonymous with the colors. Dutch pink is yel low; verditer is blue; lake is not purple-blue always, but sometimes green, yellow, brown, etc.; or it may be found as a pigment color, with a chalk base, or body, for fugitive colors.

Before proceeding to describe the actual method of mixing, a few general remarks on colors may be given. White lead is used for the base of paints, because that pigment possesses greater covering properties—or body, as it is technically termed—than any other. Zinc white may be used for a base under certain conditions, and color mixed with it will not be so likely to fade as when mixed with lead. The tendency of zinc white, however, to chip and crack ren ders the addition of lead necessary in most cases. When practicable, the natural earth pigments should be used for tinting purposes, in prefer ence to those which are manufactured. Raw umbers, raw siennas, etc., will be found to last longer than burnt umbers and burnt siennas. As a rule, burnt umber should not be used for outside painting, but the required shade should be obtained by mixing lamp-black and an oxide color, such as Venetian red.

COM111011 colors include lampblack, red lead, white lead, Venetian red, umbers, and all other common ochres, such as greys, buffs, stones, etc. Superior or ornamental colors include bright yellows, warm tints, blues, mineral greens, etc. Some colors—such as verditer, pea greens, rich reds, pinks, and bright blues—are charged at a higher rate still as delicate tints.

In compounding pigments for painting, there is yet a further matter requiring some little consideration by the worker. All blue pigments are not chemically suitable for mixture with yellows or reds, nor all yellows with reds—in fact, a knowledge of the chemical source and affinities of pigments is almost a necessity to the painter and decorator. As the briefest and simplest way of aiding the student, it will be well to mention those ordinary pigments which it is usually advisable not to mix together.