ases the
fastness of the finished black to light, the best proportions to add
are from 2 lb. to 4 lb. for 100 lb. of wool. The shade obtained in the
above recipe is of a bluish-violet hue, if a jet black be wanted, add
5 lb. of fustic to the dye-bath. Another and very common method of
working is the "stuffing and saddening" process, given in the next
recipe.

_Iron Logwood Black_.--Make a bath of 50 lb. logwood, 6 lb. fustic,
and 1 lb. sumac. Work the wool in this for one hour at the boil, lift,
allow the bath to become cool, then add 6 lb. of copperas (ferrous
sulphate) and 2 lb. bluestone; re-enter the wool, raise the
temperature to the boil, and work half an hour, then lift, wash and
dry. On the whole the first method is the most economical and yields
the best blacks, fastest to rubbing.

The iron-copper-logwood blacks are not so fast to acids as the
chrome-logwood blacks, but they are rather faster to light and air,
and equally so to scouring and milling.

One-bath methods of dyeing blacks are sometimes preferred by wool
dyers. Of these the following is an example.

_Logwood Black_.--Make a dye-bath with 50 lb. logwood, 5 lb. fustic,
6 lb. copperas, 2 lb. copper sulphate, and 4 lb. oxalic acid. Enter
the goods and work at the boil to shade. The oxalic acid is added for
the purpose of retaining the logwood-iron-copper black lake, which is
formed on mixing the various ingredients together in solution. On
boiling the wool in the liquor the fibre gradually extracts out the
dye matter and becomes dyed. The use of some of the so-called (p. 088)
"direct blacks" (_noir reduit_, Bonsor's black) is based on the same
principle.

These dyes are mixtures of logwood, fustic or other dye-stuff with
copperas, bluestone and oxalic acid, and only require adding to water
to make the dye-bath. This method of working enables logwood to be
used in conjunction with dihydroxynaphthalene and some other coal-tar
derivatives to obtain blacks of good solidity and much faster to
light, air, acids and scouring than the ordinary logwood blacks.

Another recipe for a one-bath logwood black, using the extracts in
place of the dye-wood itself, is the following:--

_Logwood Black_.--Prepare a dye-bath with 12 lb. logwood extract,
2 lb. fustic extract, 6 lb. copperas, 4 lb. bluestone, 3 lb. oxalic
acid, 2 lb. tartar. Boil the goods in this for one hour.

Some dyers use the dye-woods and prepare from them a decoction by
boiling in water