Frankfort Black is said to be 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 of vine twigs and tendrils, which contain tartar; also from peach-stones, etc. whence almond black; and the Indians employ for the same purpose the shell of the cocoa-nut: and inferior Frankfort black is merely the levigated charcoal of woods, of which the hardest, such as the box and ebony, afford the best. Fine Frankfort black, though almost confined to copperplate printing, is one of the best black pigments we possess, being of a fine neutral colour, next in intensity to lamp-black, and more powerful than that of ivory. Strong light has the effect of deepening its colour; 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 greys formed therewith is attrimineral black above, combined with iron and alluvial clay. It is found in most countries, and should be washed and exposed to the atmosphere before it is used. Sea-coal, and innumerable black mineral substances, have been and may be employed as succedanea for the more perfect blacks, when the latter are not procurable, which rarely happens.