YELLOW MINERAL PIGMENTS.
As was the case with white pigments, so with yellow: of the large
number known very few are in extensive use. In former times the number
of yellow pigments employed in painting was far greater than at
present; several, formerly in general use, have dropped out, partially
or entirely, owing either to their poisonous character or to their
replacement by others, deeper and more handsome. Especially since the
discovery of cadmium yellow and the development of the manufacture of
chrome yellows, many colours once in general use have properly fallen
into disuse.
Again, unfortunately, the most important of the yellow mineral pigments
contain lead, and have little stability; but a series of yellow colours
free from lead is known, and though some of them are inferior in shade
to the lead pigments they surpass the latter in permanence.
In addition to lead compounds, pigments derived from barium, zinc,
antimony and cadmium are in general use. The yellow lead pigments were
formerly preferred, and at present, so far as concerns beauty, they
must be regarded as superior to other mineral yellows. The endeavour
to provide the artist with permanent colours has resulted in the use
of others, perhaps less brilliant, but very lasting. Under the name of
chrome yellow a single pigment consisting of lead chromate was formerly
understood; to-day, under this title is comprised a series of pigments
containing zinc or barium in place of lead, but all commercially known
as chrome yellow.