Naples-yellow,
Light-oker,
Brown-oker,
Yellow-orpiment, or,
King’s-yellow,
Red-orpiment,
are all perfectly good and necessary for our purpose.
Naples-yellow is the only colour that ought to be used in composing
the tenderer flesh tints of women; it proves a very tender, bright
and beautiful lasting colour for all manner of painting, if properly
prepared and managed, if not, a dirty, weak and treacherous one, and
particularly in oil. It is a mineral compound of lead, antimony,
sulphur, and some arsenic, which latter is the cause of its changing,
and hurting other colours, and particularly the white, so much
complained of by the painters.
Though this yellow fixed with wax will not change; yet it will not be
amiss to insert a method to clean, and purify it, so as to render it
beautiful and lasting for oil and other uses. To clean it do as follows.
Take crude Naples-yellow, (the heaviest for bulk is the best) and break
it into small pieces with the mallet upon the grinding stone, put it
in a clean earthen vessel, and pour over it a quantity of new milk,
sufficient to cover it three or four inches over, stirring it well for
some time with a wooden spatula or stick; then let all together stand
undisturbed for five or six days, and the milk will become thick and
sour, and master by its acidity the noxious saline principles of the
colour; having stood the abovementioned time, take off the creamy part
from the top of the milk, and pour warm water upon it, and let the
vessel overflow till you perceive the water to come off as clear as
when poured on, and the colour will be purified and fit for use.
Light-oker, a precipitated, feruginous earth, answers in encaustic all
the purposes it does in oil.
Brown-oker, a precipitated feruginous earth too, only it partakes a
little of a vitrioline principle, which the light-oker does not. In
encaustic this colour answers all the purposes it does in oil.
Yellow orpiment, or king’s-yellow. The principal constituent particles
of this colour are, sulphur and arsenic, which latter prevails and
makes great havock among the other colours when used in oil; it cannot
play the same tricks fixed with wax; wax being a closer and unvariable
body, confines its arsenical principle. Oil once dry ceases to be oil,
and can confine them no longer.
Red-orpiment, so called to distinguish it from the other, is properly
not red, but of a rich orange colour, and is a compound of arsenic and
sulphur too; but here sulphur prevails, which is the reason of its
standing its ground better and doing less harm in oil than the other.
In encaustic it is of universal use, throughout a whole picture to give
warmth to lights and shades; in landscapes it may be used from the
horizon down to the fore ground, to good purpose; for shades in flesh
it is admirable, it gives a clear, soft and transparent strength; in
the verdure of landscapes it answers all the ends for brown-pink, when
mixed with a little bone black.
This colour is very conspicuous in all the warmer landscapes of Claude
Lorraine; Mr. Vernet a famous French painter uses it very much.