Old Fustic
Fustic is the wood of Morus tinctoria, a tree of Central America. It
is used principally for wool. With Bichromate of Potash as mordant,
Old Fustic gives old gold colour. With alum it gives yellow, inclining
to lemon yellow. The brightest yellows are got from it by mordanting
with tin. With copper sulphate it yields olive colours (4 to 5 per
cent copper sulphate and 3 to 4 per cent tartar). With ferrous
sulphate darker olives are obtained (8 per cent ferrous sulphate). For
silk it does not produce as bright yellows as weld, but can be used
for various shades of green and olive. Prolonged dyeing should always
be avoided, as the yellows are apt to become brownish and dull.