The method of application will be gleaned from the recipes given below.

_Black_.--Prepare a dye-bath with 5 lb. Chromotrop S, 1/4 lb. Azo (p. 093) Yellow, 50 lb. Glauber's salt. Work for one and a half hours at the boil, then add 4 lb. sulphuric acid. Work at the boil for another half hour, then lift. Add to the same dye-bath 3 lb. bichromate of potash.

Re-enter the goods and work at the boil for half an hour, then lift, rinse and dry.

_Jet Black_.--Mordant the wool by boiling for one hour in a bath made from 4 lb. bichromate of potash and 3 lb. of tartar. Then rinse, and dye in a bath containing 3-1/2 lb. Diamond Black, 1-1/4 lb. Alizarine Cyanine R R R double, and 1 lb. Gambine Yellow, working at the boil for from one to one and a half hours.

_Diamond Black on Wool_.--Mordant by boiling for one hour with 3 lb.

bichromate of potash, 1 lb. oxalic acid. Wash and dry in a bath made with 2 lb. Diamond Black, 2 lb. acetic acid. Work at 120 F. for one hour, then heat to boil, and work until the dye is fully fixed. Lift, wash and dry.

A more common method of using the Diamond Black is given in the following recipe.

_Diamond Black_.--Prepare a dye-bath with 10 lb. Glauber's salt, 2-1/2 lb. Diamond Black, 1/2 lb. Diamond Green. Boil for an hour, then pa.s.s through a fresh bath of 2 lb. bichromate of potash for three-quarters of an hour at the boil; wash and dry.

This gives a fine jet shade of black, quite fast to a strong milling, and to light, alkalies and acids. Diamond Black by itself gives bluish shades. This dye is much used in the hat-dyeing trade.

_Violet Black_.--Mordant the wool by boiling for one and a half hours in a bath made with 3 lb. fluoride of chrome and 1 lb. oxalic acid, then rinse and dye in a bath containing 25 lb. Alizarine Cyanine Black G, 5 lb. acetate of ammonia, and 1 lb. acetic acid, working at the boil for one and a half hours. A fine full shade is obtained (p. 094) which is quite fast to acids, milling and light.

_Brown Black_.--Mordant the wool as in the last recipe, then dye in a new bath 25 lb. Alizarine Cyanine Black G, 3 lb. Anthracene Brown, 5 lb. acetate of ammonia, and 1 lb. acetic acid, working at the boil for one to one and a half hours.

_Jet Black_.--Mordant as in either of the above recipes, then dye in a bath containing 20 lb. Alizarine Black S W, and 2 lb. acetic acid.

This black possesses a great degree of resistance to acid, alkali, milling and light, and is one of the best blacks at the disposal of the dyer.

_Reddish Black on Wool_.--Prepare the dye-bath containing 5 lb.

Chromotrop 2 B, 10 lb. Glauber's salt, and 4 lb. sulphuric acid, work at the boil for one hour, then lift. Add to the same bath 3 lb.

bichromate of potash and 1 lb. sulphuric acid, and work half an hour longer.

_Blue Black_.--Make the dye-bath with 6 lb. Chromotrop 10 B and 4 lb.

sulphuric acid; dye, and develop the black by adding to the same bath 3 lb. bichromate of potash and 1 lb. sulphuric acid.

_Jet Black_.--Prepare the dye-bath with 5-1/2 lb. Chromotrop S, 1/4 lb. Alizarine Yellow G G W, 10 lb. Glauber's salt, and 4 lb.

sulphuric acid. Slowly raise to the boil and work for one hour, then add to the same dye-bath 3 lb. bichromate of potash, and 1 lb.

sulphuric acid, working at the boil for one hour.

These are but a few examples of how the Chromotrops (one of the most interesting series of dye-stuffs at the service of the dyer) may be used to dye blacks. They of themselves dye brilliant reds, from bright scarlet (2 R), crimson (6 B), and purple (8 B and 10 B), to maroon and clarets (S and S B). These being turned black on being chromed, give various shades--blue blacks, violet blacks, and jet blacks, which have the merit of being fast to acids, strong milling, and light in a great degree. The blue and violet blacks may be converted to jet (p. 095) shades by adding to the dye-bath some yellow dye-stuff, such as Azo 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 B N, 10 lb. Glauber's salt, 2 lb.

oxalate of ammonia and 5 lb. acetic acid, after dyeing, and the dye-bath, is exhausted of colour, add 1-1/2 lb. bichromate of potash and 3 lb. hydrochloric acid, and boil again for half an hour. Finish in the usual way.

One of the reasons for adding the oxalate of ammonia, is to precipitate out any lime which may be in the water in such a form that it will not react with the dye-stuff.

_Fast Black_.--Mordant the yarn with copperas (sulphate of iron). Dye in a bath with 5 lb. Gambine Y, 2 lb. Acid Mauve, 2 lb. bisulphate of soda. Proceed as described for full green.

_Blue Black_.--3-1/2 lb. Naphthylamine Black S, 10 lb. Glauber's salt, and 5 lb. acetic acid; to fully exhaust the dye-bath add 8 lb.

bisulphate of soda.

_Jet Black_.--5 lb. Naphthylamine Black S, 1/4 lb. Fast Acid Green B N, 10 lb. Glauber's salt, and 5 lb. acetic acid, adding 8 lb.

bisulphate of soda to exhaust the bath.

_Blue Black_.--Give a deep blue bottom in the indigo vat and dye with 2 lb. Anthracite Black B, 10 lb. Glauber's salt and 2 lb. acetic acid.

#Greys on Wool.#--The dyeing of greys follows very naturally after (p. 097) the dyeing of blacks, for from a broad point of view greys are simply light blacks, and any dye-stuffs that will dye black will if used in smaller proportions give greys. There is a great variety of tone among greys: reddish greys, bluish greys, greenish greys, and so on. They may be dyed in a considerable variety of ways from a large number of dye-stuffs, both natural and artificial. Of these two cla.s.ses the latter gives the best result as far as regards brightness of tone, and as regards other properties the greys obtained from the artificial coal-tar colours are fully equal to those from natural dyes.

A large number of recipes are in use by dyers for the production of greys, so many that it becomes almost an impossibility to do more than give a mere fraction of them here. However, a number of representative recipes will be given, covering all cla.s.ses of dye-stuffs capable of being used for the purpose, and thus forming a guide to the methods of dyeing and the proportions of dye-stuffs to be used.

_Light Grey_.--Dye at the boil for three-quarters of an hour, in a bath containing 1 lb. perchloride of tin, 3 lb. alum, 3 oz. indigo extract, and 2 oz. cochineal.

_Slate Grey_.--Mordant by boiling with 4 lb. alum and 1 lb. argol, then dye with 6 lb. logwood, 6 oz. cudbear and 3 oz. indigo extract.

_Slate Grey_.--Another method is to boil the wool with 10 lb. logwood, 2 lb. Glauber's salt and 1 lb. sulphuric acid for three-quarters of an hour, then lift, add 1 lb. copperas, and re-enter the wool, working at the boil for three-quarters of an hour, then lift, wash and dry.

_Reddish Grey_.--Boil for an hour with 10 lb. fustic, 11 lb. cutch, 1/2 lb. bichromate of potash and 1-1/2 lb. copperas.

_Pearl Grey_.--Give a light blue ground in the indigo vat, then dye in a new bath with 2 lb. muriate of tin and 3/4 lb. cochineal, working at the boil to shade.

_Silver Grey_.--Prepare a bath with 3/4 lb. tannic acid; work for (p. 098) an hour in a warm bath, then sadden with 3 lb. nitrate of iron to shade, then lift, wash and dry.

_Pearl Grey_.--Prepare a bath with 3 lb. fluoride of chrome and 4 lb.

Alizarine Bordeaux B. Enter into the bath when cold, then heat to the boil and work for one and a half hours, then lift, wash and dry.

_Silver Grey_.--The dye-bath is made with 3 lb. fluoride of chrome and 6-1/2 oz. Alizarine Cyanine G G, the dyeing being done as in the last recipe.

_Greenish Grey_.--A good shade is dyed with 3 lb. fluoride of chrome, 4 oz. Alizarine Bordeaux B, and 4 oz. Diamond Flavine G, working as given in the above recipe.

_Grey_.--Give a pale blue bottom with an indigo vat, then dye in a bath containing 1 lb. fluoride of chrome, 1/2 oz. Diamine Fast Red F, and 3/4 oz. Anthracene Yellow C; work at the boil for one hour, lift, wash, and dry.

_Dark Grey_.--A very fine dark grey, almost approaching a black is obtained by the following plan: bottom the wool with a medium blue by means of the indigo vat, dye in a bath containing 1 lb. fluoride of chrome, 3 oz. Diamine Fast Red F, and 3 oz. Anthracene Yellow C.

_Slate Grey_.--A good slate grey of a slightly greenish tone can be dyed in a bath of 5 lb. acetate of ammonia, 3/4 lb. Acid Blue 4 S, and 1/4 lb. t.i.tan Brown R, working at the boil to shade.

_Pale Slate Grey_.--The dyeing is done in a bath made with 5 lb.