Bistre. A warm brown water-colour-pigment, made of the soot of beech-wood, water, and gum. It is the mediæval fuligo and fuligine.
Biting-in. The action of aqua fortis upon copper or steel in engraving.
Bitumen. This pigment should be genuine Asphaltum, diluted and ground up with drying oil or varnish. It dries quickly. There is a substance sold as bitumen which will not dry at all. (See Asphaltum.)
Bivium, R. (via, a way). A street or road branching out into two different directions; at the corner there was almost always a fountain.
Bizarre, Fr. Fantastic, capricious of kind.
Black is the resultant of the combination in unequal proportions of blue, red, and yellow.
Black, in Christian art, expressed the earth; darkness, mourning, wickedness, negation, death; and was appropriate to the Prince of Darkness. White and black together signify purity of life, and mourning or humiliation; hence adopted by the Dominicans and Carmelites. In blazonry, black, called sable, signifies prudence, wisdom, and constancy in adversity and love, and is represented by horizontal and perpendicular lines crossing each other.
Black Pigments are very numerous, of different degrees of transparency, and of various hues, in which either red or blue predominates, producing brown blacks or blue blacks. The most important are beech black, or vegetable blue black; bone black, or Paris black, called also ivory black; Cassel or Cologne black, cork black, Frankfort black, and lamp-black. (See Asphaltum.)
Blades, Arch. The principal rafters of a roof.
Blasted, Her. Leafless, withered.