painting materials
and that it was employed in the East many centuries before it was known in
Europe. R. Pfister ('Materiaux pour server au classement des Textiles Egyptiens
posterieurs a la Conquete Arabe/ Revue des Arts Asiatiques, X [1936], pp. 1-16)
says that lac dye was brought from India and introduced into the West by the
Arabs after their invasion of Egypt and the fall of Alexandria in the VII
century.
Lake, as a term, may be applied to any pigment which is made by precipi-
tating an organic coloring matter or dye upon a base or substrate which is usually
an insoluble, finely divided, semi-transparent, inorganic inert, such as aluminum
hydrate or calcium sulphate. The word is derived from the Italian, Iacca_y which,
in turn, seems to be associated with 'lac* from India, the source of a red dye (see
Lac Lake), as well as ordinary shellac (see Thompson, The Materials of Medieval
Painting^ p. 109). The earliest lakes were made from such natural dyes (see
Laurie, Materials of the Painter's Craft, pp. 253-278), but now they are prepared
in enormous quantities from synthetic dyestuffs. The true lake is a transparent
color precipitated on a transparent base like aluminum hydrate, but the word
has been extended to include those colors struck on barytes, tin oxide, zinc oxide,
and a number of other materials which produce pigments with body and hiding
power (see Beam, p. 133). The same dye often produces different shades and
different hues with different bases (see also Coal-Tar Colors and Mordant).
Lamp Black (see also Carbon Black) is nearly pure (over 99 per cent), amor-
phous carbon which is collected in brick chambers from the condensed smoke of
a luminous flame from burning mineral oil, tar, pitch, or resin. It is not quite a
true black but is slightly bluish in color, and makes good neutral grays. Micro-
scopically, it is very finely divided, uniform, and homogeneous; in mounting
mediums, the particles appear to collect in chains and filaments. It does not wet
well with water on account of the slight amount of unburned oil it contains.
The preparation of lamp black (atramentum} from burning resin and pitch, as
well as the preparation of other blacks, is described by Pliny the Elder (see
Bailey, II, 87 and 216).
Lapis Lazuli (see Ultramarine Blue, natural).
Lemon Yellow (see Barium Yellow and Strontium Yellow).
Light Red (see Iron Oxide Red) is a term sometimes used to indicate a red
ochre prepared by calcining yellow ochre; it is a light, warm red, the hue depend-
ing upon the degree of calcination. Today the term is also used for a processed
blend of ferric oxide and calcium sulphate which is almost identical in compo-
sition with Venetian red (see Venetian Red).
Lime White (see Chalk).
Litharge (see Massicot).
lithol Red or Lithol Toner is one of the most important and widely used of
the synthetic red dyestuffs in the modern lake pigment industry. It is i-sulpho-
^naphthalene-azo-/3-naphthol, C_20H_14NAS (Colour Index, p. 43), It is prepared