Chapter IV (1)

THE PRINCIPLES AND PRACTICE OF COTTON DYEING.

Students of cotton dyeing should have a good knowledge of the principles that underlie the processes of dyeing cotton fabrics. It is only by recognising these principles and then endeavouring to apply them to each individual case of dyeing, that the dyer or student will obtain a thorough grasp of his subject. It is the aim of the author to lay down these principles in a clear and intelligible form. Cotton is dyed in its loose raw condition, as yarn in the form of hanks, yarn in the form of cops, and in the woven pieces of every kind. Formerly the idea was prevalent among cotton dyers that the process which succeeds with piece goods would not answer with yarns. It is now recognised however that this is not so, that a process which will dye cotton yarn will also dye cotton piece goods or loose cotton. The differences which do exist in the practical working of the processes entirely arise from the difference in the form in which the cotton is presented to the dyer, for it must be obvious to any one that the mode of handling a piece of cotton cloth during the time it is in the dye-bath must be different from that of a hank of yarn, a parcel of loose cotton or a number of cops. The various machines used for dyeing all these forms and the manner of working them have been already described.

The dyes, whether natural--derived from the various dye-woods, etc.--or artificial--prepared from coal tar--may according to their varied chemical composition and constitution be divided into seventeen or eighteen distinct groups, but it is not intended here to give any account of them; the reader is referred to other books such as _The Dictionary of Coal Tar Colours_, by George H. Hurst; _The Chemistry of Coal Tar Colours_, by Benedikt and Knecht; or _The Chemistry of Organic Colouring Matters_, by Nietzki, where the composition and properties of the dyes are fully described.

From the manner in which the various dyes are applied to cotton, linen, wool and other fibres we can divide them into five groups, thus:--

Group 1. Direct dyes.
" 2. Basic dyes.
" 3. Acid dyes.
" 4. Mordant dyes.
" 5. Miscellaneous dyes.

First group, direct dyes, are now very numerous; they dye cotton, linen and other vegetable fibres from a plain bath, and do not require those fibres to be prepared in any way. Hence the reason of their being named direct, or by some the substantive colours. They will also dye wool and silk.

The second group, basic dyes, comprise some of the oldest of the coal-tar dyes; they dye wool and silk direct from plain baths, but require cotton, linen and other vegetable fibres to be previously prepared in baths of tannic acid, sumach or other tanning material.

The third group, acid dyes, are very numerous, and from both their chemical composition and mode of dyeing can be divided into several sub-groups. Their principal feature is that they dye wool and silk from baths containing Glauber's salt and some acid, hence their name of "acid dyes". They do not dye cotton or linen well, some not at all, others are absorbed to a slight extent by the cotton, but only pale tints are produced, while others may be used along with metallic mordants to dye bright but pale and fugitive shades. The acid dyes comprise such as Acid green, Formyl violet, Acid magenta, Azo scarlet, Orange. Thiocarmine R., Patent blues, Wool greens, indigo extract, Eosines, etc.

The fourth group, mordant dyes, includes the alizarine series of coal-tar colours, logwood, Brazil wood and most natural colours, and some others. The principal feature of these dyes is that they require the cotton to be prepared with some metallic oxide, like those of chrome, alumina and iron, before dyeing, and the colour which is got depends partly upon the particular dye-stuff used and partly upon the oxide with which the cotton has been prepared.

The fifth group includes a few dyes like indigo, which are dyed on to cotton by various and special processes.

The processes of cotton dyeing employed to-day may be comprised under eight heads, namely:--

(1) Direct dyeing. (2) Direct dyeing followed by fixation with metallic salts. (3) Direct dyeing followed by fixation with developers. (4) Direct dyeing followed by fixation with couplers. (5) Dyeing on tannic mordant. (6) Dyeing on metallic mordant. (7) Developing the colour direct on fibre. (8) Dyeing by impregnating the cotton with the dye-stuff, followed by oxidation or steaming.

It is of course not easy to elaborate a simple scheme of grouping the processes that shall definitely include all processes, but the above grouping will be found as successful as any, and each will be considered as fully as is deemed necessary.

(1) DIRECT DYEING.

Nothing in the history of cotton dyeing caused such a revolution in the methods of working as did the introduction some fifteen years ago of the forerunners (Congo red, Benzo purpurine, Chrysamine, Azo blue) of the now numerous group of direct dyes, followed as they were by the Benzo, Congo, Diamine, Titan, Chicago and Zambesi members of the group. Prior to their introduction cotton dyeing was always more or less complicated and mordanting methods had to be employed.

With the introduction of the direct dyes cotton dyeing has become even more simple than wool or silk dyeing, and now all that is necessary is to prepare a dye liquor containing the necessary amount of dye-stuff and Glauber's salt, or common salt or soda, or some similar body, or a combination thereof. The method of working is to place the cotton in a lukewarm or even in a hot bath, raise to the boil, allow the goods to remain in the boiling bath for half an hour to an hour, then take them out, wring, wash and dry. This method is simple and will answer for all the dyes of this group. There are some that do not require the working to be done boiling; it is simply needful to enter the cotton into a boiling bath and work without steam until the bath has cooled down. Furious boiling is not needed--a gentle simmer gives the best results. Uneven dyeing seems to be an impossibility in this group of dyes, unless the cotton is dirty; no matter how the operations are carried on, level dyeing is the rule not the exception. An enormous variety of shades and tints can be obtained from these dyes, and they can be combined together in every conceivable manner and proportions.

No satisfactory explanation has yet been given as to what feature in the chemical composition of these dye-stuffs give them such an affinity for the cotton fibre as to enable them to dye in so simple a manner such fast shades as they do; it is a fact there is such an affinity and there the matter must rest.

It has been found in practice that the efficiency of the dyeing operation depends, primarily of course, on the particular dye-stuff used, but also upon other factors, that a certain assistant be used. Some dyes work on the cotton better from a bath containing Glauber's salt, while with others common salt works best, while a little soda along with the salt facilitates the dyeing in some cases. It is practically impossible to specify here the best assistant for all the direct colours, on account of the great number of such dyes which are known, but in the practical recipes given below much useful advice will be found. Then the quantity of such assistants used is of much importance; there is one proportion at which the best results are obtained for each dye. The dyer should find out for himself by experiment and the use of the dyes he employs in his work what assistant and how much is best, and make his baths up to that strength. With some dyes 10 per cent. of the assistant will be found sufficient, while with others, 25 to 30 per cent. will not be too much. The percentage refers to the weight of the cotton that is taken.

One function of the assistants must be pointed out here: it is that in some cases they--especially the alkaline ones, soda, potash, borax, phosphate of soda--help the dyeing by promoting the solubility of the dye-stuff in the bath, thereby retarding the exhaustion of the bath and ensuring the production of level shades.

The following formulas show the application of the foregoing principles to the dyeing of numerous shades on to cotton and also the dyes which are applicable, some of the combinations which are possible with these direct dyes, and give some idea of the tints and shades of the colours that can be got by their means. The best assistants to use are also indicated in the formulæ.

All the formulæ here given and all that will be given in future chapters are intended for 100 lb. weight of cotton fabrics in any condition, whether of loose cotton, yarn in cops, hanks or wraps and woven fabrics of every kind.

_Bright Red._--Dye with 3 lb. Benzo purpurine 4 B, 3 lb. soda and 15 lb. Glauber's salt. This dye may also be used with 3 lb. soap and 10 lb. soda in the bath with equally good results.

_Pale Salmon._--Prepare a dye-bath with 3 lb. salt, 5 lb. phosphate of soda, 1 lb. soap, 1/2 oz. Benzo orange R. For a pale shade like this it is not necessary to heat to the boil, a temperature of 170° to 180° F. is sufficient.

_Dark Plum._--Prepare a dye-bath with 20 lb. of Glauber's salt, 2-1/2 lb. soap, 1-1/2 lb. Diamine black R O. and 2 lb. Diamine red N. Enter at 180° F., work for a few minutes, then raise to boil and dye to shade; lift, wash and dry.

_Turkey Red._--Prepare a dye-bath with 1-1/2 lb. Benzo purpurine 4 B, 1 lb. Brilliant purpurine, 2 lb. soap, 10 lb. borax. Enter the cotton at the boil and work for one hour; lift, wash and dry.

_Lilac Red._--Prepare the dye-bath with 2 lb. soap, 5 lb. soda, 3 lb. Rose azurine G. Work at the boil for one hour.

_Pink._--Prepare a bath containing 10 lb. soda, 1 oz. Rose azurine B. Enter at a boil and work for one hour, boiling to shade; lift, wash and dry.

_Bordeaux._--Prepare a dye-bath with 15 lb. Glauber's salt, 5 lb. soda crystals, 3 lb. Diamine fast red F, 1 lb. Diamine violet N, 1 lb. Rose azurine G. Enter cold, then raise to the boil, and work for one and a half hours; lift, wash and dry.

_Rose Pink._--The dye-bath is made with 2 lb. Erika B, 20 lb. Glauber's salt and 3 lb. soap, working at near the boil to shade.

_Brilliant Red._--Make the dye-bath with 24 lb. Brilliant purpurine R and 25 lb. Glauber's salt, working at the boil for one hour.

_Deep Pink._--Make the dye-bath with 1/2 lb. Diamine rose B D, 1/2 lb. soda, 1 lb. soap and 5 lb. Glauber's salt, working at 150° F. for half an hour.

_Dark Red._--Use in the dye-bath 3 lb. Diamine red 5 B, 2 lb. soda and 20 lb. Glauber's salt, working at the boil for one hour.

_Pink._--Prepare the dye-bath with 4 oz. Diamine rose B D, 1 lb. Turkey-red oil, 40 lb. Glauber's salt. Dye at the boil for one hour.

_Scarlet._--Prepare the dye-bath with 4 lb. Diamine scarlet 3 B, 1 lb. Turkey-red oil, 20 lb. Glauber's salt. Dye at the boil for one hour.

_Scarlet._--Prepare the dye-bath with 3 lb. Titan scarlet C, 1/2 lb. Titan orange, 50 lb. salt. Work at the boil for thirty minutes, then lift, wash and dry. The dye-bath is not exhausted and may be used for further lots.

_Crimson Red._--Prepare the dye-bath with 5 lb. Titan scarlet D and 50 lb. salt. Work at the boil for fifty minutes, then lift, wash and dry. The bath is not exhausted, the cotton taking up only about 3 lb. of the dye-stuff; it may therefore be kept for further use, when for each succeeding lot 3 to 3-1/2 lb. of colour and 25 lb. of salt only need be added.

_Scarlet._--Prepare the dye-bath with 5 lb. Rosophenine 5 B, dissolved in 50 gallons hot water, 2 gallons caustic soda lye (60° Tw.). When thoroughly dissolved add 150 lb. salt. Make up the bath to 100 gallons. Enter the yarn and work for a quarter to half an hour at about 180° F; squeeze off and wash thoroughly in cold water until the water runs off clean.

_Rose Red._--Use 1 lb. Diamine red 10 B, 3 lb. soda, and 20 lb. Glauber's salt.

_Deep Crimson._--Use 3 lb. Diamine red 10 B, 3 lb. soda and 20 lb. Glauber's salt.

_Claret._--Use 3 lb. Diamine Bordeaux B, 3 lb. soda and 20 lb. Glauber's salt.

_Pink._--The dye-bath is made with 5 oz. Dianil red 4 B, 5 lb. salt and 3 lb. soda.

_Scarlet._--Use in the dye-bath 3 lb. Dianil red 4 B, 15 lb. salt and 5 lb. soda. Work at the boil for one hour.

_Claret._--Dye with 1-1/2 lb. Dianil claret G, 3 lb. soda and 20 lb. salt. Work at the boil for one hour.

_Maroon._--Dye with 3 lb. Dianil claret B, 3 lb. soda and 20 lb. salt. Work at the boil for one hour.

_Bright Scarlet._--Use in the dye-bath 2-1/2 lb. Dianil red 4 B 5 oz. Dianil orange G, 3 lb. soda and 15 lb. salt.

_Dark Maroon._--Make the dye-bath with 1 lb. Dianil red 4 B, 2 lb. Dianil claret G, 13 oz. Dianil claret B, 5 lb. soda and 20 lb. salt.

_Crimson._--Dye with 3 lb. Congo rubine, 5 lb. soda and 20 lb. Glauber's salt.

_Dark Maroon._--Use in the dye-bath 1 lb. Benzo purpurine 4 B, 3 lb. Congo Corinth G, 3 lb. soda and 20 lb. Glauber's salt, working at the boil to shade.

_Pale Fawn Red._--Use in the dye-bath 1-1/2 oz. Diamine red 5 B, 1-1/2 oz. Diamine catechine G, 3 lb. soda and 10 lb. Glauber's salt.

_Rose Red._--Prepare the dye-bath with 3/4 lb. Diamine Bordeaux B, 3 oz. Diamine orange B, 3 lb. soda and 20 lb. salt.

_Crimson._--Use in the dye-bath 3/4 lb. Diamine Bordeaux B, 3 oz. Diamine fast yellow B, 3 lb. soda and 20 lb. Glauber's salt.

_Salmon._--Dye with 1-1/2 oz. Diamine fast red F, 1-1/2 oz. Diamine fast yellow B, 3 lb. soda and 10 lb. Glauber's salt.

_Terra-Gotta Red._--Dye with 1-1/2 lb. Diamine brown M, 3/4 lb. Diamine fast red F, 3 lb. soda and 20 lb. Glauber's salt.

_Lilac Red._--Dye with 4 lb. Heliotrope B B, 3 lb. soda and 15 lb. Glauber's salt.

_Bright Pink._--Use in the dye-bath 2 oz. Rose azurine G, 1 lb. soda and 10 lb. Glauber's salt. Nearly all the direct reds give good pink tints when used in proportion, varying from 0.1 to 0.25 per cent. of dye-stuff.

_Bright Straw._--Dye in a bath made of 1/4 lb. Titan yellow G G, 10 lb. salt, for three-quarters of an hour, then lift, wash and dry.

_Yellow._--Prepare a dye-bath with 1 lb. Titan yellow Y, 10 lb. salt. Heat to 180° F., enter the goods, raise to boil, and dye for one hour; lift, wash and dry.

_Yellow._--Prepare the dye-bath with 1/4 lb. Diamine fast yellow A, 1 lb. Turkey red oil, 20 lb. Glauber's salt. Dye at the boil for one hour.

_Sun Yellow._--Prepare the dye-bath with 2 lb. Sun yellow, 30 lb. common salt. Dye at the boil. The bath is kept for further lots.

_Yellow._--Prepare the dye-bath with 1 lb. Direct yellow R, 20 lb. Glauber's salt. Dye at the boil for one hour.

_Yellow._--Prepare the dye-bath with 2 lb. Curcuphenine, 20 lb. common salt. Work at the boil for one hour; lift, rinse and dry.

_Old Gold._--Make the dye-bath with 5 lb. Diamine yellow N powder, 20 lb. phosphate of soda, 10 lb. soap. Work at the boil for one hour; finish in the usual way. The bath may be kept for other lots of goods.

_Dark Yellow._--The bath is made from 2 lb. Toluylene orange G, 10 lb. phosphate of soda, and 2-1/2 lb. soap, working at the boil to shade.

_Bright Yellow._--Use 1 lb. Chrysophenine, 2 lb. phosphate of soda and 10 lb. Glauber's salt.

_Lemon Yellow._--Use 1 oz. Chrysamine G, 2 lb. phosphate of soda and 10 lb. Glauber's salt.

_Yellow._--Dye with 2 lb. Oxyphenine and 20 lb. salt.

_Yellow Olive._--Use in the dye-bath 2 oz. Cotton brown N, 4-1/2 oz. Diamine bronze G, 4-1/2 oz. Diamine fast yellow B, 3 lb. soda and 20 lb. salt.

_Green Yellow._--Dye with 1/2 lb. Diamine fast yellow B. 2 oz. Diamine bronze G, 3 lb. soda and 10 lb. Glauber's salt.

_Gold Yellow._--Use in the dye-bath 3 lb. Columbia yellow, 3 lb. soda and 20 lb. Glauber's salt.

_Cream._--Dye with 1/2 oz. Toluylene orange G, 24 grains Brilliant orange G, 1 lb. soda and 10 lb. Glauber's salt.

_Primrose._--Dye with 3 oz. Dianil yellow 3 G, 2 lb. soda and 10 lb. salt.

_Gold Yellow._--Dye with 2-1/2 lb. Dianil yellow G, 1/2 lb. soda and 15 lb. salt.

_Buff Yellow._--Dye with 3-1/2 oz. Dianil yellow 2 R, 1/2 lb. soda and 10 lb. salt.

_Orange._--Prepare the dye-bath with 2 lb. Chlorophenine orange R, 20 lb. common salt. Work at the boil for one hour; lift, rinse and dry.

_Red Orange._--Make the dye-bath with 3 lb. Mikado orange 4 R and 25 lb. salt. Work at the boil for one hour.

_Orange._--Make the dye-bath with 3 lb. Mikado orange G and 25 lb. salt. Work at the boil for one hour.

_Pale Orange._--The dye-bath contains 6 oz. Diamine Orange G, 1-1/2 oz. Diamine fast yellow B, 1/4 oz. Diamine scarlet B, 3 lb. soda and 15 lb. Glauber's salt.

_Olive Yellow._--Dye with 3/4 lb. Diamine fast yellow B, 1 oz. Oxydiamine black N, 1-1/2 oz. Diamine bronze G, 3 lb. soda and 20 lb. Glauber's salt.

_Dark Orange._--Dye with 3 lb. Columbia orange R, 3 lb. soda and 20 lb. Glauber's salt at the boil for one hour.

_Bright Orange._--Use 3 lb. Congo orange R, 3 lb. soda and 20 lb. Glauber's salt at the boil for one hour.

_Pale Orange._--Dye with 3 lb. Dianil orange 2 R, 2 lb. soda and 10 lb. salt at the boil for one hour.

_Brilliant Orange._--Dye with 4 lb. Dianil orange G and 20 lb. salt for one hour.

_Deep Orange._--Dye with 2 lb. Oxydiamine orange R, 3/4 lb. soda and 20 lb. salt for an hour.

_Pale Orange._--Dye with 3/4 lb. Diamine fast yellow B, 1 lb. Diamine orange B, 3 lb. soda and 15 lb. Glauber's salt.

_Bright Orange._--Dye with 1-1/2 lb. Benzo orange R, 1-1/2 lb. Chrysamine R, 10 lb. phosphate of soda and 2 lb. soap.

_Green._--Prepare the dye-bath with 2 lb. Benzo green G, 10 lb. Glauber's salt. Enter lukewarm, bring slowly to the boil, dye for one hour at the boil.

_Russian Green._--Make the dye-bath with 16 oz. Diamine black H W, 4 oz. Diamine fast yellow A, 3 lb. soda, 15 lb. Glauber's salt, working at the boil for one hour, then lift, wash and dry.

_Dark Olive._--Prepare a dye-bath with 3-1/2 lb. Benzo olive, 2-1/2 lb. Diamine black B O, 2 lb. Diamine yellow, 20 lb. common salt, 2 lb. soap. The goods are entered into the bath at 160° F., then heat is raised to the boil, and the dyeing continued for one hour, then lift, wash and dry.

_Dark Olive._--Dye in a bath of 2 lb. Titan yellow Y, 1 lb. Diamine brown Y, 1-1/2 lb. Diamine blue 3 B, 2 lb. soda. Work for one hour, then lift, wash and dry.

_Olive._--Prepare a dye-bath with 15 lb. phosphate of soda, 3 lb. soap, 1-1/2 lb. Diamine yellow N, 4 oz. Diamine blue 3 B, 1-1/2 oz. Diamine brown V. Dye at the boil to shade; lift, wash and dry.

_Green Olive._--Prepare the dye-bath with 1 lb. Diamine black R O, 1 lb. Chrysamine, 1/4 lb. Benzo brown, 5 lb. soda, 5 lb. salt, 2 lb. soap. The goods are entered at about 180° F. and worked for a short time, then the temperature is raised to the boil, and the goods are worked for one hour, lifted, washed and dried.

_Reseda._--Prepare a bath with 10 lb. Glauber's salt, 2 lb. soap, 1/2 lb. Diamine black R O, 2 lb. Diamine yellow N. Enter at 120° F., heat to boil and dye for one hour at that temperature; lift, wash and dry.

_Sage Green._--Prepare a dye-bath with 10 lb. Glauber's salt, 1/2 lb. Diamine black R O, 2 lb. Diamine yellow N. Enter at about 150° F. and then raise to boil and dye boiling for one hour, wash and dry.

_Drab._--Prepare the dye-bath with 10 lb. Cross dye drab, 5 lb. soda crystals. Enter at the boil and work at this temperature for half an hour. Whilst dyeing add gradually 75 lb. salt. Rinse well and dry.

_Olive._--Prepare the dye-bath with 2 lb. Dianil olive, 5 lb. phosphate of soda, 5 lb. common salt. Dye at the boil for one hour.

_Olive._--The dyeing is done in a bath containing 4 oz. Diamine black H W, 1-3/4 lb. Diamine bronze G, 5 lb. soda, 15 lb. Glauber's salt. Work at the boil for one hour.

_Grass Green._--Make the dye-bath with 2 lb. Chrysamine G, 1-1/2 oz. Benzo azurine G, 3 lb. soap and 10 lb. borax, working at the boil for one hour.

_Green._--Make the dye-bath with 2 lb. Titan yellow Y, 1 lb. Titan blue 3 B and 20 lb. salt.

_Bright Grass Green._--Dye for an hour at the boil with 1 lb. Sulphon azurine D, 2 lb. Thiazole yellow and 20 lb. Glauber's salt.

_Green._--Use in the dye-bath 3 lb. Diamine green B, 3 lb. soda and 20 lb. Glauber's salt, working at the boil to shade.

_Dark Green._--Dye with 3 lb. Diamine dark green N, 3 lb. soda and 20 lb. Glauber's salt.

_Green._--Use in the bath 3 lb. Benzo green B B, 3 lb. soda and 20 lb. Glauber's salt at the boil for one hour.

_Dark Sea Green._--Dye with 5 oz. Diamine black H W, 3 oz. Diamine catechine G, 3 oz. Diamine fast yellow B, 3 lb. soda and 10 lb. Glauber's salt.

_Pale Green._--Use in the dye-bath 3 lb. Diamine fast yellow B, 2 oz. Diamine black H W, 3 lb. soda and 10 lb. Glauber's salt.

_Bright Pea Green._--Use in the dye-bath 1 oz. Thioflavine S, 1/4 oz. Diamine sky blue F F and 20 lb. Glauber's salt.

_Dark Green._--Use 1-3/4 lb. Diamine green G, 3/4 lb. Oxydiamine yellow G G, 3 lb. soda and 20 lb. Glauber's salt, working at the boil for one hour.

_Deep Green._--Use 1-3/4 lb. Diamine green G, 3/4 lb. Diamine black B H, 1/2 lb. Oxydiamine yellow G G, 3 lb. soda, and 20 lb. Glauber's salt.

_Sea Green._--Use 2 oz. Dianil yellow R, 2-1/2 oz. Dianil blue B, 1-3/4 oz. Dianil dark blue R, 1 lb. soda, and 20 lb. salt, working at the boil.

_Leaf Green._--Dye with 1-1/2 lb. Dianil yellow 3 G, 1 lb. Dianil blue B, 11 oz. Dianil blue 2 R, 3 lb. soda, and 20 lb. salt at the boil for one hour.

_Deep Green._--Dye with 2-1/2 lb. Dianil yellow 3 G, 2-1/2 lb. Dianil blue 2 R, 6 oz. Dianil dark blue R, 3 lb. soda, and 20 lb. salt at the boil for one hour.

Greens are largely produced by mixing yellows and blues together as will be seen from the recipes given above; the particular shade of green which is got from a combination of blue and green depends upon the quality of the dye-stuffs used: thus, to produce bright greens of a pure tone, it is essential that the yellow used shall have a greenish tone like Thioflavine S, Thiazole yellow, or Dianil yellow 3 G, while the blue must also have a greenish tone like Diamine sky blue, Benzo blue 3 B, etc. By using yellows like Diamine fast yellow R, and dark blues like Benzo azurine 3 R, Diamine blue R W, Dianil dark blue R, the green which is got is darker and duller in tone. The addition of such a dye as Diamine black B H throws the shade more on to an olive, while a brown dye-stuff, like Diamine brown M, or an orange dye, like Titan orange N, throws the green on to a sage tone. Examples of these effects will be found among the recipes given above.

It may be added here that by using smaller quantities, but in the same proportions as given in the above recipes, a great range of tints and shades of green can be dyed from very pale to very deep.

_Bright Blue._--Prepare a dye-bath with 1/2 lb. Congo blue 2 B, 5 lb. salt, 5 lb. phosphate of soda, 2 lb. soap. Work at the boil for one hour, then rinse and dry.

_Dark Navy._--Prepare a dye-bath with 1 lb. Diamine black R O, 2 lb. Diamine blue 3 R, 8 lb. Glauber's salt, 2 lb. soap. Enter the cotton at 180° F., and boil for one hour.

_Pale Blue._--Prepare a dye-bath with 10 lb. salt, 3 lb. soda, 3 oz. diamine blue 3 R. Work for one hour at the boil, then lift, wash and dry.

_Sky Blue._--Prepare a dye-bath with 2 lb. Titan como G, 20 lb. common salt, 2 oz. acetic acid. Work at the boil for half an hour, then lift, wash and dry.

_Bright Blue._--Prepare the dye-bath with 1-1/2 lb. Chicago blue 6 B, 20 lb. Glauber's salt, 3 lb. soap. Work at the boil for one hour, then lift, wash and dry.

_Pale Sky Blue._--Make the dye-bath with 1 oz. Chicago blue 6 B, 10 lb. Glauber's salt, 2 lb. soap. Work at the boil for one hour, then lift, wash and dry.

_Sky Blue._--Prepare the dye-bath with 1 lb. Diamine sky blue F F, 1 lb. Turkey-red oil, 20 lb. Glauber's salt. Dye at the boil for one hour.

_Dark Blue._--Prepare the dye-bath with 2-1/2 lb. Diamineral blue R, 2-1/2 lb. Diamine deep black Cr, 1 lb. Turkey-red oil, 40 lb. Glauber's salt. Dye at the boil for one hour.

_Dark Blue._--Prepare the dye-bath with 3 lb. Triamine black B, 15 lb. Glauber's salt, in 50 gallons of water. Enter at 150° F., and boil for one hour. Allow the goods to remain until the water is cold, when the dye-bath will be completely exhausted.

_Blue._--Prepare the dye-bath with 2 lb. Diamine steel blue L, 2 lb. soda, 15 lb. Glauber's salt. Dye at the boil for one hour.

_Blue._--Prepare the dye-bath with 4 lb. Diamine blue B G, 2 lb. soda, 20 lb. Glauber's salt. Dye at the boil for one hour. In shade this is very similar to that got with Diamine brilliant blue G, which however should be used for light shades on account of its brightness. For deep shades Diamine blue B G, is preferable, because of its greater tinctorial power.

_Light Indigo Blue._--Prepare the dye-bath with 1 lb. Paramine indigo blue, 2 lb. soda, 20 lb. Glauber's salt. Enter at about 150° F., and dye at the boil for one hour.

_Navy Blue._--Prepare the dye-bath with 4 lb. Paramine navy blue R, 2 lb. soda, 20 lb. Glauber's salt. Enter at about 150° F., and dye at the boil for one hour.

_Blue._--Prepare the dye-bath with 1 lb. Paramine navy blue R, 2 lb. soda, 20 lb. Glauber's salt. Enter at about 150° F., and dye at the boil for one hour.

_Navy Blue._--Prepare the dye-bath with 4 lb. Benzo chrome black blue B, 15 lb. Glauber's salt, 3 lb. soda. Work at the boil for one hour; lift, rinse and dry.

_Grey Blue._--Prepare the dye-bath with 2 lb. Paramine blue black S, 2 lb. soda, 20 lb. Glauber's salt. Enter at 150° F., and dye for one hour at boil.

_Blue._--Prepare the dye-bath with 1 lb. Paramine blue B, 2 lb. soda, 20 lb. Glauber's salt. Enter at about 150° F., and dye at the boil for one hour.

_Slate Blue._--Prepare the dye-bath with 1/4 lb. Diamine black B H, 3/4 oz. Diamine fast yellow B, 2 lb. soda, and 10 lb. Glauber's salt. Dye at the boil to shade.

_Deep Blue._--Use 3-1/4 lb. Diamine blue B X, 1/2 lb. Oxydiamine black N, 3 lb. soda and 20 lb. Glauber's salt at the boil for one hour.

_Blue._--Dye at the boil for one hour with 1-1/2 lb. Diamine sky blue, 2 oz. Diamine green B, 2 lb. soda and 10 lb. Glauber's salt.

_Navy._--Dye with 1 lb. Dianil dark blue R, 8 oz. Dianil black C R, 5 lb. soda and 20 lb. salt at the boil for one hour.

_Dark Navy._--Use 2 lb. Dianil blue B, 2 lb. Dianil dark blue R, 3/4 lb. Dianil black C R, 2 lb. soda and 25 lb. salt, working at the boil for one hour.

_Deep Blue._--Dye with 3-1/2 lb. Diamine blue black E, 5 lb. soda and 20 lb. Glauber's salt at the boil for one hour.

_Deep Blue._--Dye with 3 lb. Zambesi black B R, 3 lb. soda and 20 lb. Glauber's salt at the boil for one hour.

_Dark Navy._--Use 3 lb. Dianil dark blue R, 3 lb. caustic soda 70° Tw., and 25 lb. salt, working at the boil for one hour.

_Violet Blue._--Dye with 3 lb. Dianil dark blue 3 R and 25 lb. salt at the boil for one hour.

_Bright Blue._--Use 1 lb. Dianil blue B, and 20 lb. salt, working at the boil for one hour.

_Full Blue._--Dye with 3 lb. Brilliant azurine 5 G, 5 lb. common salt, 5 lb. phosphate of soda and 2 lb. soap at the boil for one hour.

_Dark Blue._--Dye with 3 lb. Erie blue B X, 3 lb. soda and 20 lb. Glauber's salt at the boil for one hour.

_Pale Blue._--Dye with 1 lb. Chicago blue 6 B, 3 lb. soda and 20 lb. salt at the boil for one hour.

_Deep Blue._--Dye with 1-1/2 lb. Oxydiamine black A, 2 lb. Diamine deep blue R, 3 lb. soda and 20 lb. Glauber's salt at the boil for one hour.

_Blue._--Dye with 6 oz. Diamine blue 3 B, 1-1/2 oz. Diamine sky blue F F, 3 lb. soda and 10 lb. Glauber's salt.

_Navy._--Dye with 4 lb. Diamine new blue R, 3 lb. soda and 20 lb. Glauber's salt at the boil for one hour.

_Dark Navy._--Dye with 1-3/4 lb. Diamineral blue R, 3 lb. soda and 20 lb. Glauber's salt at the boil for one hour.

_Sky Blue._--Prepare the dye-bath with 6 oz. Diamine sky blue F F, 3 lb. soda and 10 lb. Glauber's salt, working at the boil for one hour.

_Dark Blue._--Use in the dye-bath 3 lb. Diamine blue R W, 2 lb. soda and 20 lb. Glauber's salt, working at the boil for one hour.

_Dark Blue._--Prepare the dye-bath with 3 lb. Triamine black B T, and 15 lb. Glauber's salt; work at the boil to shade.

_Blue._--Use 2 lb. Direct indigo blue and 15 lb. Glauber's salt; work at the boil.

_Bright Blue._--Use in the dye-bath 3 lb. Titan como S N, 2 lb. acetic acid and 20 lb. salt, working at the boil for one hour.

_Turquoise Blue._--Dye with 1 lb. Diamine sky blue, 1 oz. Diamine fast yellow B, 2 lb. soda and 10 lb. Glauber's salt, working at the boil to shade.

_Dark Navy._--Use 4 lb. Titan navy R, and 20 lb. salt at the boil for one hour.

_Green Blue._--Dye with 1 lb. Dianil blue G, 2-1/2 oz. Dianil yellow G, 1 lb. soda and 20 lb. salt at the boil for one hour.

Many more formulæ could have been given, but the above will perhaps suffice; they include all the best of the direct blues. Paler tints of blue may be got by using from 1 to 2 per cent. of any of these blues and also of the many direct blacks now on the market. The direct blues as a rule have a good degree of fastness to light.

_Lilac._--Prepare a dye-bath with 1/4 lb. Hessian brown 2 M, 1 oz. Azo mauve A M, 1 lb. soap, 2 lb. soda, 10 lb. salt. Work at the boil for one hour, then lift, wash and dry.

_Plum._--Dye with 3 lb. Oxydiamine violet G, 3 lb. soda and 20 lb. salt.

_Dark Plum._--Use in the dye-bath 3 lb. Oxydiamine violet B, 3 lb. soda and 20 lb. Glauber's salt, working at the boil.

_Violet._--Make the dye-bath with 3/4 lb. Oxydiamine violet B, 1 lb. soda and 10 lb. Glauber's salt, and dye at the boil to shade.

_Violet._--Dye with 12 oz. Dianil blue 4 R, 2 oz. Dianil blue B and 10 lb. salt at the boil.

_Lilac._--Dye with 1-1/2 oz. Diamine rose G D, 3/4 oz. Diamine sky blue F F, 1 lb. soda and 10 lb. Glauber's salt at the boil to shade.

_Red Violet._--Make the dye-bath with 1/2 lb. Diamine violet N, 1/2 oz. Diamine brilliant blue G, 1 lb. soda and 10 lb. Glauber's salt, working at the boil.

_Red Violet._--Dye with 1 lb. Diamine violet N, 1 lb. soda and 10 lb. Glauber's salt.

_Bright Red Lilac._--Dye with 1-3/4 lb. Erika B N, 4 oz. Chicago blue 4 R, 3 lb. soda and 20 lb. Glauber's salt at the boil.

_Grey Lilac._--Dye with 12 oz. Neutral grey G, 3 oz. erika B N, 1 lb. soda and 10 lb. Glauber's salt at the boil for one hour.

_Pale Lilac._--Dye with 2-1/2 oz. Dianil claret B, 2-1/2 oz. Dianil blue 4 R, and 10 lb. salt.

_Light Plum._--Dye with 10 oz. Dianil claret B, 10 oz. Dianil blue and 20 lb. salt.

_Dull Lilac._--Dye with 1/2 lb. Diamine brown V, 1 lb. soda and 10 lb. Glauber's salt.

_Heliotrope._--Dye with 4 oz. Heliotrope 2 B, 1 lb. soda and 10 lb. Glauber's salt.

_Plum._--Dye with 3 lb. Congo Corinth B, 3 lb. soda and 10 lb. Glauber's salt.

_Dull Violet._--Use in the dye-bath 1-1/2 lb. Chicago blue 4 R, 14 oz. Erika B N, 3 lb. soda and 20 lb. Glauber's salt, working at the boil for one hour.

_Red Lilac._--Dye with 6 oz. Oxydiamine violet G, 2 oz. Oxydiamine violet B, 1 lb. soda and 10 lb. Glauber's salt at the boil for one hour.

_Violet._--Dye with 3 oz. Diamine violet N, 2 oz. diamine blue 3 R, 1 lb. soda and 10 lb. Glauber's salt.

_Fawn Drab._--Prepare a dye-bath with 1 lb. Cachou de laval, 1/4 oz. Benzo purpurine B. Enter the cotton into this bath in the cold and heat to the boil, taking about one hour for the operation, then add 4 lb. common salt and boil for three-quarters of an hour longer; lift, wash and dry.

_Pale Olive Brown._--The dye-bath is made with 1 lb. Diamine bronze G, 1 oz. Cotton brown N, 3 oz. Diamine gold, 5 lb. soda, 15 lb. Glauber's salt. Work at the boil for one hour, then lift, wash and dry.

_Red Brown._--Prepare a dye-bath with 1-3/4 lb. Cotton yellow, 4 lb. Hessian brown 2 B N, 2 lb. Diamine black R O, 1 lb. soda, 2 lb. salt. Enter the goods at 180° F., then raise to the boil and work to the shade; lift, wash and dry.

_Brown Drab._--Prepare a dye-bath with 1/4 lb. Cotton brown N, 3/4 oz. Diamine yellow N, 3/4 oz. Diamine black B O, 15 lb. phosphate of soda, 3 lb. soap. Work at the boil for one hour.

_Gold Brown._--Prepare the dye-bath with 16-1/4 oz. Toluylene orange G, 9-1/2 oz. Toluylene orange R, 4-3/4 oz. azo mauve, 2-1/2 lb. soap, 5 lb. soda. Dye at the boil for one hour.

_Chestnut Brown._--Prepare a dye-bath with 10 lb. common salt, 2 lb. Benzo brown G, 1/2 lb. Benzo azurine G, 1/2 lb. Chrysophenine. Enter the goods at 150° F., raise to the boil and dye boiling for one hour.

_Purple Brown._--Prepare a dye-bath with 10 lb. common salt, 2 lb. Benzo brown N B, 1 lb. Azo violet. Enter the cotton at 150° F., raise to the boil and dye boiling for an hour; lift, wash and dry.

_Brown._--Prepare a dye-bath with 5 lb. soda, 10 lb. Glauber's salt, 12 oz. Chrysamine, 1 oz. Benzo purpurine, 6-1/4 oz. Benzo azurine. Dye at the boil for one hour, rinse and dry. The brown thus got is fast to washing.

_Dark Chestnut Brown._--Prepare a dye-bath with 10 lb. salt, 3 lb. Benzo brown N B X, raise to 150° F., enter goods, heat to boil, and work for one hour; lift, rinse and dry.

_Dark Brown._--Prepare a dye-bath with 20 oz. Glauber's salt per gallon of water used, 2-1/2 lb. soap, 1-1/2 lb. Diamine black R O, 2 lb. Cotton brown N. Enter the yarn at 180° F., give three turns, raise temperature to boil, and work to shade; lift, rinse and wash.

_Gold Brown._--Prepare the dye-bath with 4 lb. Titan gold, 50 lb. salt. Work at the boil for thirty minutes, then lift, wash and dry. The dye-bath is not exhausted, only about 3 lb. of the colour being taken up by the cotton. It may, therefore, be kept for further lots, adding 3 lb. more colour and about 20 lb. more salt for each batch of cotton, or if it is not desired to keep the bath, add less colour to start with, and towards the end of the operation add more salt.

_Brown._--Prepare the dye-bath with 4 lb. Paramine brown G, 20 lb. Glauber's salt, 2 lb. soda. Dye at the boil for one hour.

_Light Brown._--Prepare the dye-bath with 3 lb. Diamine catechine G, 3 lb. soda, 15 lb. Glauber's salt. Dye at the boil for one hour.

_Dark Brown._--Prepare the dye-bath with 5 lb. Diamine catechine B, 3 lb. soda, 15 lb. Glauber's salt. Dye at the boil for one hour.

_Dark Drab._--Prepare the dye-bath with 1 lb. Titan brown Y, 3 oz. Columbia green, 32-3/4 oz. Diamine bronze, 17 lb. Glauber's salt. Work at the boil for one hour, then lift, wash and dry.

_Pale Brown._--The dye-bath is made with 2 lb. Mikado orange 4 R, 3 oz. Benzo fast grey, 30 lb. Glauber's salt. Work at the boil for one hour, then lift, ash and dry.

_Gold Brown._--Make a dye-bath with 1 lb. Titan gold, 50 lb. common salt. Enter at the boil, work for an hour, then lift, wash and dry. Keep the bath for another lot of goods; it will only require the addition of about 14 oz. of colour and 10 lb. salt.

_Buff Brown._--Make the dye-bath with 3/4 lb. Titan gold, 1/4 lb. Titan brown R, 5 oz. Titan blue 3 B, 40 lb. common salt. Work at the boil to shade, then lift, wash and dry.

_Deep Chestnut Brown._--Make the dye-bath with 3 lb. Titan brown R, 1-1/2 lb. Titan blue R, 25 lb. common salt. Work at the boil for an hour, then lift, wash and dry.

_Light Seal Brown._--Make the dye-bath with 10 lb. salt, 2 lb. soda, 14 oz. Oxyphenine, 3/4 lb. Atlas red R, 6 oz. Diamine blue B X. Work at the boil to shade, then lift, wash and dry.

_Orange Brown._--Make a dye-bath with 10 lb. salt, 2 lb soda, 14 oz. Oxyphenine, 1 lb. Atlas red R, 1 oz. Diamine blue B X. Work at the boil to shade, then lift, wash and dry.

_Pale Nut Brown._--Use in the dye-bath 4-1/2 oz. Diamine catechine G, 1 oz. Diamine brown M, 1 oz. Diamine catechine B, 2 lb. soda and 10 lb. Glauber's salt, working at the boil for one hour.

_Walnut Brown._--Dye with 1 lb. Diamine brown M, 3 oz. Diamine orange G, 2 oz. Diamine black H W, 2 lb. soda and 10 lb. Glauber's salt at the boil for one hour.

_Black Brown._--Use in the dye-bath 3 lb. Diamine brown M, 3/4 lb. Diamine blue black R, 3 lb. soda and 20 lb. Glauber's salt, working at the boil.

_Reddish Brown._--Dye with 2 lb. Dianil brown R, 5 lb. salt and 5 lb. phosphate of soda at the boil for one hour.

_Chocolate Brown._--Dye with 2 lb. Dianil brown T, 5 lb. phosphate of soda and 5 lb. salt at the boil for one hour.

_Dark Brown._--Dye with 2 lb. Dianil dark brown, 5 lb. salt and 5 lb. phosphate of soda at the boil for one hour.

_Light Brown._--Prepare the dye-bath with 5 lb. Diamine catechine G, 3 lb. soda and 15 lb. Glauber's salt.

_Brown._--Dye with 2-1/4 lb. Cotton brown N, 4 oz. Diamine black H W, 2 lb. soda and 20 lb. Glauber's salt at the boil for one hour.

_Dark Walnut Brown._--Make the dye-bath with 3-1/4 lb. Diamine brown M, 6 oz. Diamine catechine B, 6 oz. Diamine red 5 B, 2 lb. soda and 20 lb. Glauber's salt; work at the boil.

_Dark Chestnut Brown._--Dye with 2-1/2 lb. Dianil brown R, 1 lb. soda and 20 lb. salt at the boil.

_Dark Brown._--Dye with 2 lb. Dianil brown 3 G O, 2 lb. Dianil brown B D, 1 lb. Dianil red 4 B, 3 lb. soda and 25 lb. salt at the boil for one hour.

_Brown._--Prepare the dye-bath with 5 lb. Mikado brown M and 25 lb. salt; work the cotton in this at the boil for one hour.

_Nut Brown._--Use in the dye-bath 2-1/2 lb. Benzo brown G and 15 lb. salt, working at the boil.

_Dark Brown._--Use in the dye-bath 3 lb. Benzo brown N B and 15 lb. Glauber's salt, working at the boil.

_Dark Brown._--Make the dye-bath with 4 lb. Diphenyl brown B N, 10 lb. Glauber's salt and 4 lb. soap, working at the boil to shade.

_Black Brown._--Use in the dye-bath 2-1/2 lb. Dianil brown 3 G O, 1-1/2 lb. Dianil brown G, 3/4 lb. Dianil dark blue R, 3 lb. soda and 25 lb. salt.

_Dark Brown._--Dye with 1-1/2 lb. Zambesi black D, 1-1/4 lb. Brilliant orange G, 3 lb. soda and 20 lb. Glauber's salt at the boil to shade.

_Gold Brown._--Dye with 2 lb. Curcumine S, 1 lb. Columbia orange R, 5 oz. Columbia black F B, 3 lb. soda and 15 lb. Glauber's salt at the boil.

_Dark Chestnut._--Dye at the boil with 2 lb. Columbia Orange R, 8 oz. Columbia black F B, 2 lb. soda and 10 lb. Glauber's salt.

_Sage Brown._--Dye with 1 lb. Zambesi black D, 1 lb. Curcumine S, 3/4 lb. Diamine orange G D, 3 lb. soda and 30 lb. Glauber's salt at the boil.

_Deep Brown._--Dye 3-1/2 lb. Diamine brown M, 3/4 lb. Oxydiamine orange G, 3/4 lb. Diamine black H W, 3 lb. soda and 20 lb. Glauber's salt at the boil.

_Chestnut._--Dye with 2-1/2 lb. Diamine brown G, 3/4 lb. Oxydiamine orange R, 3 lb. soda and 20 lb. Glauber's salt.

_Pale Walnut Brown._--Dye with 3-1/2 lb. Diamine brown M, 3/4 lb. Oxydiamine orange G, 1-1/2 oz. Diamine black B H, 3 lb. soda and 20 lb. Glauber's salt.

Various other browns may be obtained by combining the various direct browns together or with other direct dyes. The use of a yellow or orange will brighten them; that of a red will redden the shade; the addition of a dark blue or a black will darken the shade considerably. It may be useful to remember that a combination of red, orange and blue or black produces a brown, and by using various proportions a great range of shades can be dyed.

_Black._--Prepare a dye-bath with 6 lb. Diamine black R O, 2 oz. Thioflavine S, 2 lb. soap, 10 lb. salt. Enter the cotton at the boil and dye for one hour; lift, wash and dry.

_Black._--Prepare the dye-bath with 5 lb. Direct deep black E extra, and 1/2 to 1-1/2 oz. common salt per gallon of water. Dye at the boil for one hour.

_Deep Black._--Prepare the dye-bath with 5-1/2 lb. Diamine deep black R B, 2 lb. soda, 20 lb. Glauber's salt. Dye at the boil for one hour; lift, wash and dry.

_Black._--Prepare the dye-bath with 5 lb. Direct triamine black G X, 15 lb. Glauber's salt. Dye for one hour at the boil; lift, rinse and dry. In working for from two to three hours the dye-bath will exhaust completely.

_Black._--Prepare the dye-bath with 5 lb. Oxydiamine black A, 20 lb. Glauber's salt, 2 lb. soda. Dye at the boil for one hour.

_Black._--Prepare the dye-bath with 6 lb. Pluto black B. Dye at the boil for one hour with the addition of 3/4 to 1-1/4 oz. Glauber's salt, 1/2 to 3/4 oz. soda ash per gallon of liquor. To develop the shade it is necessary to dye in a boiling liquor.

_Black._--Use 2-1/2 lb. Diamine jet black Cr, 2-1/2 lb. Diamine jet black R B, 2 lb. soda, and 20 lb. Glauber's salt, working at the boil for one hour.

_Black._--Use 6 lb. Oxydiamine black N R, 2 lb. soda and 20 lb. Glauber's salt, working at the boil for one hour.

_Black._--Use 6 lb. Columbia Black F B B, 3 lb. soda and 20 lb. Glauber's salt, working at the boil to shade.

Besides the blacks given in the above recipes, there are other brands which are used in the same way, and vary slightly in the shade of black they give.

All the direct blacks require working in strong baths to give anything like black shades; they all have, more or less, a bluish tone, which can be changed to a jetter shade by the addition of a yellow or green dye in small proportions, which has been done in one of the recipes given above.

By coupling, chroming or developing, the direct blacks can be made to give full, deep and fast blacks, and examples of their use in this manner will be found in following sections.

By using all the direct blacks in proportions varying from 1/4 to 1 per cent. of dye-stuff to the weight of the cotton they give greys of various tints and depths; a few examples of such greys will now be given.

_Blue Grey._--Prepare the dye-bath with 1/2 lb. Oxydiamine black A, 1 lb. soda, 10 lb. Glauber's salt. Dye at the boil for one hour.

_Bright Grey._--Prepare a dye-bath with 4-1/2 oz. Azo mauve A M, 1-1/2 oz. Direct yellow G, 3 lb. soda, 15 lb. common salt.

_Silver Grey._--Prepare the dye-bath with 1/2 oz. Neutral grey G, 10 lb. sulphate of soda. Work at the boil to shade, then lift, wash and dry.

_Slate._--Dye in a bath with 1/2 lb. Diamine black B H, 3 oz. Diamine bronze G, 15 lb. Glauber's salt at the boil for three-quarters of an hour.

_Bronze Grey._--Prepare a dye-bath with 1/2 lb. Diamine bronze G, 15 lb. Glauber's salt, 3 lb. soap. Enter at about 160° F., raise to boil and work for one hour; lift, wash and dry.

_Dark Slate._--Prepare a dye-bath with 10 lb. Glauber's salt, 1-1/2 lb. soap, 1 lb. Diamine black R O, 2 lb. Cotton brown N. Heat to about 150° F. Enter the goods, work for a short time, then raise to the boil and work for one hour; lift, wash and dry.

_Green Grey._--Prepare a dye-bath with 10 lb. Glauber's salt, 1 lb. Diamine black R O, 3/4 oz. Thioflavine S. Enter at from 150° Tw. to 180° F., raise to boil and dye for one hour; wash and dry.

_Light Slate._--Prepare a dye-bath containing 2-1/4 lb. soap, 15 lb. Glauber's salt, 6 oz. Diamine black R O, 1/2 oz. thioflavine S. Enter cotton at 140° F., work a little, then heat to boil and dye to shade; lift, wash and dry.

_Grey._--Prepare the dye-bath with 1/2 lb. Diamine grey G, 1/2 oz. Diamine scarlet B, 1 lb. soda, 1 lb. soap, 5 lb. Glauber's salt. Dye for one hour at the boil.

_Light Grey._--Prepare the dye-bath with 1 lb. Diamine grey G, 1 lb. soda, 1 lb. soap, 5 lb. Glauber's salt. Dye for one hour at the boil; lift, rinse and dry.

It may be convenient here to deal with the question of the fastness of the direct dyes to such influences as light, air, acids, alkalies, washing and soaping, that have a very material influence on the use of these dyes in dyeing various fabrics. This matter can only be dealt with here in very general terms, for space is limited and the dyes are too numerous for detailed mention. They vary very greatly in degrees of fastness, some are absolutely fast to all influences; the blacks are among the fastest, generally these resist washing and soaping, stand acids well and are fast to alkalies, light however affects them more or less, though they cannot be reckoned fugitive colours. The few direct greens known are good colours; they stand washing, soaping and light well, but they are affected by acids and alkalies. The blues vary very much, generally they stand soaping and have a fair degree of fastness to light, acids have but little action, alkalies tend to redden the shade, while heat also affects them. The direct browns are very variable; they are in general not fast to light; they stand washing and soaping and resist alkalies, but are altered by acids slightly. The yellows rank among the fastest of colours to light and washing and soaping; acids have but little effect; they are reddened by alkalies. Among the reds there is great variation in properties, generally they are not fast to light, standing washing and soaping well and resisting weak alkalies; some of them, such as the Benzo purpurines and Congo reds are very sensitive to acids, being turned blue with very weak acids, but on washing or soaping the original colour comes back; others, like the Titan reds, Diamine reds and Delta purpurines are not so sensitive, but these are affected by moderately strong acids; there are one or two reds like Benzo fast scarlet 4 B S and Purpuramine D H, which are fast to acids. The depth of shade which is dyed has some considerable influence on the degree of fastness, the deeper shades of a colour are always faster than the paler shades, particularly as regards light, a difference of 1/2 per cent, of dye-stuff has been known to make a very appreciable degree of difference as regards the fastness of a colour to light.

In dyeing cotton with all the direct dyes, it is found that the whole of the dye-stuff is not removed from the dye-bath, how much is taken up by the cotton, and the depth of the shade which is dyed upon the cotton chiefly depends upon three factors:--

(1) Volume of water used. (2) Quantity of saline salts used. (3) Degree of affinity of the dye-stuff for the fibre.

There may also be some minor factors such as temperature at which the dyeing is carried on, the character and condition of the fabrics being dyed, etc.

The volume of water used in making the dye-bath has a very great influence upon the amount of dye taken up by the cotton, the greater the volume of water the less dye is absorbed and the paler the colour which is produced upon the fibre. It is therefore important to use as little water as possible in making up the dye-bath, indeed, for anything like good results to be obtained with some dyes, especially those of the sulphur series like Vidal black, Immedial blacks, Katigen browns, Cross-dye blacks, Amidazol blacks, etc., it is necessary to employ what is called a short bath, that is making it as strong as possible. The proportion of water with such dyes should not exceed fifteen times the weight of the cotton being dyed, that is, for every pound of cotton, 1-1/2 gallons of water can be allowed. This will suit the dyeing of yarns and loose fabrics like knitted stockings and hosiery goods very well. In the case of dyeing piece goods on a jigger or continuous dyeing machines even stronger liquors can be used with advantage. With some of the older, direct dyes like Congo red, Benzo azurine, Diamine scarlets, the proportion of water may be increased to twenty times the weight of the cotton. In any case the quantity of water used should not exceed twenty-five times the weight of the cotton.

The second factor, the quantity of saline salts, like Glauber's salt, soda, borax, etc., added in the dyeing, is not without influence, generally the more that is added the more dye there is left in the bath, but here again much depends upon the salt and the colouring matters used. Some salts, more particularly Glauber's salt and common salt, tend to throw some dye-stuffs out of the bath, and so the more there is used of them the deeper the shade produced on the fabric. It is quite impossible, having regard to the scope of this book, to deal with this question in detail. The dyer should ascertain for himself the best salts and the best proportions of these to use with the particular dyes he is using. The recipes given above will give him some ideas on this point.