A dark blackish brown and somewhat bituminous earth, inclining a little
towards purple, is a very good colour, and of singular use where
extraordinary strength is required in fore grounds.
UMBRA, Crude and calcined.
A useful colour enough for common purposes; some painters use it for
shades in flesh, but very improperly, for it is a very raw colour crude
or calcined, and only fit to be used in drapery or back grounds.
These are all the colours that ought to be used for painting in
encaustic, with the pencil; there are a few more that might be employed
in this manner, but as they are rather inferior in quality, or only
compounds of those already mentioned, I omit them; a few, not commonly
used in oil painting that notwithstanding might be used in encaustic, I
shall mention under the article of crayons, as they belong more to, and
are more useful in that way.