Yellow, Alizarine Yellow, or Gambine Yellow, which will resist the
action of the bichrome in the developing bath.

Chromotrop blacks while so very fast have the disadvantage of being
expensive, but by combining them with logwood it is possible to obtain
blacks that have a great degree of resistance to light, acids and
milling. They are in this respect much superior to pure logwood
blacks, while the cost is not prohibitive.

The following recipe will serve as an example of how these two
dye-stuffs may be combined:--

_Jet Black_.--Make a bath with 2 lb. Chromotrop S, 15 lb. Glauber's
salt, and 5 lb. hydrochloric acid. Work in this bath for one hour,
then add 2-1/2 lb. bichromate of potash, and work again for half an
hour, at the boil. Lift, rinse and dye in a new bath containing 25 lb.
logwood, 1 lb. fustic extract and 1/4 lb. sulphuric acid, working at
the boil for an hour.

_Violet Black on Wool_.--Dye the wool in the Chromotrop bath, and
develop as in the last recipe. The final dye-bath is made with 6 lb.
logwood, 8 oz. Patent Blue B, and 4 lb. sulphuric acid. By using
logwood alone blue blacks can be dyed, by increasing the proportion of
fustic a greener tone can be obtained, while by the use of a larger
proportion of Chromotrop a redder tone of black is the result.

_Jet Black_.--Make the dye-bath with 20 lb. Glauber's salt, and 6 lb.
Nyanza Black; when obtained is a good one and of solid appearance.
Alkalies turn it red, but it is fast to dilute acid and soaping.

_Black_.--Prepare the dye-bath with 10 lb. Glauber's salt, 5 lb.
oxalate of ammonia, 5 lb. acetic acid and 6 lb. Anthracene Chrome
Black F. Work at the boil for three-quarters of an hour, or until (p. 096)
the bath is exhausted of dye-stuff, then add 1-1/2 lb. bichromate of
potash and 2 lb. hydrochloric acid to the same bath and work for half
an hour longer.

The Anthracene Chrome Blacks, of which there are three brands, F, 5 B
and F E, are excellent dyes, producing very fine blacks, and owing to
the slowness of dyeing and great penetrative properties are very
suitable for dyeing hat felts and other closely woven fabrics. The 5 B
dyes more bluish shades than the F, while the F E brand gives full
black. By combining these with Anthracene Yellow B N, Anthracene Acid
Brown G, or other similar dyes, jet blacks can be got as per the
following recipe:--

_Jet Black_.--Make the dye-bath with 6 lb. Anthracene Chrome
Black F E, 5 oz. Anthracene Yellow