Lamp black is the soot produced by burning oil, resin, small coal, resinous woods, coal tar or tallow. It is in the state of very fine powder, works smoothly, is of a dense black color and durable, but dries very slowly in oil.
Vegetable black is a better kind of lamp black made from oil. It is very light, free from grit and of a good color. It should be used with boiled oil, driers and a little varnish. Raw linseed oil or spirits of turpentine keeps it from drying.
Ivory-black is obtained by calcining waste ivory in close vessels and then grinding. It is intensely black when properly burned. Bone-black is inferior to ivory-black, and prepared in a similar manner from bones. In Europe some other blacks are used, but are seldom met with in this country.
When camphor gum is burned and the soot collected by means of a paper funnel or a saucer inverted over it, the result mixed with gum-arabic will be found far superior to the best ivory-black.
Black japan is a composition of asphaltum and oil, and is a liquid of about the same consistency as varnish, of a jet-black color, although of a brownish tint when applied over a light color, or on tin or glass. While ordinary blacks have a greenish hue when varnished, this article will retain its jet color. It has no grains as a mixture of pigment and varnish, and its flowing qualities are good. Many err in supposing that it will cover at once, and thus take the place of color, and furnish with two or three applications a perfect surface over any ground, but this is not the case. It was never intended for such a purpose, it is semi-transparent, and when put upon a white ground produces a brownish tint or glaze.
Besides the black pigments described above, there are several other substances known as Prussian black, black lake and tannin black, which have been proposed as black pigments, but their use is so limited that it is not necessary to give a description of them.
Frankfort black is made of the lees of wine, from which the tartar has been washed, by burning in the manner of ivory black. Similar blacks are prepared from vine twigs and tendrils which contain tartar, also from peach-stones, etc., whence almond black and peach black, and the Indians employ for the same purpose the shell of the cocoanut.
Fig. 14. Handled Roofing Brush.
Inferior Frankfort black is, in fact, merely the levigated charcoal of woods, of which the hardest, such as box and ebony, afford the best. Fine Frankfort black, though almost confined to copper-plate printers, is one of the best black pigments we possess, being of a fine neutral color, next in intensity to lamp black and more powerful than that of ivory. Strong light has the effect of deepening its color, yet the blacks employed in the printing of engravings have proved of very variable durability. It is probable that this black was used by some of the Flemish painters, and that the pureness of the grays is attributable to the property of charred substances to prevent discolorment.
Blue black is a well-burnt and levigated charcoal, of a cool neutral color, and 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 in two respects, which it owes chemically to the bleaching power of carbon, and chromatically to the neutralizing and contrasting power of black with white. A superior blue black may be made by calcining Prussian blue in a close crucible, in the manner of ivory black, and it has the important property of drying well in oil. Innumerable black pigments may be made in this way by charring.
Vegetable black is a pigment now very extensively employed, superseding to a great extent the use of lamp black, to which it is in every way superior. The best way to procure it is to buy it in a dry state, in which it resembles soot, and is so exceedingly light that an ounce or two will fill a gallon measure. It is free from grit, and only requires to be rubbed up with a palette knife on a marble slab, instead of grinding. It should never be diluted with linseed oil, because, if it were, it would never dry, and it is not advisable to employ turpentine, but always the best boiled oil, and a little varnish will improve it. A small quantity of driers should be added, to ensure its drying with a uniformity of surface.