GREEN PIGMENTS
Chromium Oxide, Viridian, Emerald Green.
Chromium Oxide is, as its name implies, an oxide of chromium; this is an opaque variety. Viridian is also an oxide of chromium, but is transparent. Both these are quite permanent.
Emerald Green is aceto-arsenite of copper, and a somewhat dangerous colour to use; it is darkened by impure air, but this is not so serious as are its effects upon other colours when mixed with them. If used at all, it should be used quite by itself, as if it is mixed with other colours it is sure to have a bad effect on them. It turns some colours black very quickly.