14. Black, the opposite extreme of white, is the last and lowest in the scale of colors. To be perfect, it must be neutral with respect to individual colors and absolutely transparent-that is, it must have the quality of absorbing all the rays of light that fall upon it, and reflect none. Its use in painting is to represent shade or depth, of which it is the governing element in colors, as white is to light.

There is, properly speaking, no perfectly black pigment. Black deteriorates all colors, more or less, with which it is mixed, by neutralizing them and rendering their color valueless. Black is what is known as a cold color, that is, devoid of the brilliancy of such colors as red, yellow, orange, etc., which are called warm colors.

Black, therefore, imparts coldness to all colors with which it is mixed-it gives, for instance, to red a purplish tinge; it turns yellow into green; and gradually neutralizes white to a bluish gray. It is the most retiring of all colors and communicates this property to other colors in mixture, but when placed alongside of other colors, heightens their effect by contrast, and, in like manner, subdues the cold colors by rendering them less conspicuous. Invested with the double office of color and shade, black is, both as regards use and avoidance, one of the most important colors to the painter.

15. Lampblack is simply the soot obtained by burning resinous woods, tallow, coal tar, etc. It is a purely carbonaceous substance of fine texture and very durable. It may be experimentally prepared by holding a plate over the flame of a candle and collecting the sooty deposit thus obtained. On a larger scale, it may be obtained by suspending a conical metal funnel over a lamp flame, fed with oil, tallow, coal tar, or crude naphtha, through a large bushy wick arranged to generate as much smoke as possible. Large, spongy, mushroom-like accumulations of an exceedingly fine and very black carbonaceous matter gradually form at the apex of the cone, and may be, from time to time, collected until a sufficient quantity is obtained. It is in this state very oily, and can be used only as an oil pigment, but if slowly calcined in closed vessels, it is rendered drier and less oily, becoming what is known as burnt lampblack, which may be used as a pigment for both oil and water colors.

16. Ivory black and bone black, though prepared by the same process, are pigments that differ materially in their intrinsic qualities. Each is prepared by charring to blackness, in a closed vessel, the material which forms its base, but though both are perfectly neutral and durable blacks, mixing well with oil, the former is superior in quality and may be mixed with certain proportions of white lead, to form a beautiful pearl gray.

Black, furnished from calcined bones, however, has a peculiar reddish tint that mars it for some purposes. It tends, unless well burnt, towards a brown color, drying slowly and unevenly. Bone black is cheaper than ivory black, and is, therefore, frequently used where the latter would be more suitable and yield better results.

17. Frankfort black is the name of a pigment prepared from the lees, or sediment of wine, vine twigs, and tendrils-from which the tartar has been washed-by burning in the same manner as ivory black. Similar blacks are also prepared from peach stones, etc., though these are usually distinguished under the names of almond black, peach black, etc., and, in India, the shell of the cocoanut is employed for the same purpose.

Fine Frankfort black, used very largely by copperplate printers, is one of the most valuable black pigments obtainable; being of a fine neutral color, next in intensity to lampblack, and is even stronger in effect than ivory black. Strong light has the effect of deepening its color, and it is probable that the grays so admired in the works of the Flemish painters, owe their pureness to the use of this pigment in the mixture of their colors.

An inferior quality of Frankfort black is made from the levigated charcoal of woods, of which the hardest, such as box and ebony, afford the best material. This quality is very largely used as the pigment for printer's ink, but is, also, occasionally used as a paint.

18. Blue black is a well burned and levigated charcoal of a cool neutral color, not differing in other respects from the common Frankfort black. Blue black was formerly much employed in painting, and, in common with all carbonaceous blacks, has, when duly mixed with white, a preserving influence upon that color. This influence is obtained from two causes, first, chemically through the bleaching power of carbon, and the other, chromatically through the neutralizing and contrasting power of black with white. A superior blue black may be made by calcining Prussian blue in a closed crucible, in the manner of ivory black, and it has the important property of drying well in oil. Innumerable black pigments may, in this way, be made by charring.