_To Dye Wool and Woollen Cloths of a Blue Color._
Dissolve 1 part of indigo in 4 parts of concentrated sulphuric acid; to the solution add 1 part of dry carbonate of potass, and then dilute it with 8 times its weight of water. The cloth must be boiled for an hour in a solution containing 6 parts of alum and 3 of tartar, for every 32 parts of cloth. It is then to be thrown into a water-bath, previously prepared, containing a greater or smaller proportion of diluted sulphate of indigo, according to the shade which the cloth is intended to receive. In this bath it must be boiled till it has acquired the wished-for color.
The only coloring matters employed in dyeing blue, are woad and indigo.
Indigo has a very strong affinity for wool, silk, cotton, and linen. Every kind of cloth, therefore, may be dyed with it without the assistance of any mordant whatever. The color thus induced is very permanent. But indigo can only be applied to cloth in a state of solution. and the only solvent known is sulphuric acid. The sulphate of indigo is often used to dye wool and silk blue, and is known by the name of Saxon blue.
It is not the only solution of that pigment employed in dyeing. By far the most common method is, to deprive indigo of its blue color and reduce it to green, and then to dissolve it in water by means of alkalies. Two different methods are employed for this purpose. The first is, to mix with indigo a solution of green oxide of iron, and different metallic sulphurets. If therefore indigo, lime, and green sulphate of iron are mixed together in water, the indigo gradually loses its blue color, becomes green, and is dissolved. The second method is, to mix the indigo in water with certain vegetable substances which readily undergo fermentation; the indigo is dissolved by means of quicklime or alkali, which is added to the solution.
The first of these methods is usually followed by dyeing cotton and linen; the second in dyeing wool and silk.
In the dyeing of wool, woad and bran are commonly employed as vegetable ferments, and lime as the solvent of the green base of the indigo. Woad itself contains a coloring matter precisely similar to indigo; and by following the common process, indigo may be extracted from it. In the usual state of woad when purchased by the dyer, the indigo which it contains is probably not far from the state of green pollen. Its quantity in woad is but small, and it is mixed with a great proportion of other vegetable matter.
When the cloth is first taken out of the vat, it is of a green color; but it soon becomes blue. It ought to be carefully washed, to carry off the uncombined particles. This solution of indigo is liable to two inconveniences: first, it is apt sometimes to run too fast into the putrid fermentation; this may be known by the putrid vapors which it exhales, and by the disappearance of the green color. In this state it would soon destroy the indigo altogether. The inconvenience is remedied by adding more lime, which has the property of moderating the putrescent tendency. Secondly, sometimes the fermentation goes on too languidly. This defect is remedied by adding more bran or woad, in order to diminish the proportion of thick lime.
_To make Chemic Blue and Green._
Chemic for light blues and greens, on silk, cotton or woollen, and for cleaning and whitening cottons, is made by the following process:
Take 1 lb. of the best oil of vitriol, which put upon 1 oz. of the best indigo, well pounded and sifted; add to this after it has been well stirred, a small lump of common pearlash as big as a pea, or from that to the size of 2 peas; this will immediately raise a great fermentation, and cause the indigo to dissolve in minuter and finer particles than otherwise. As soon as this fermentation ceases, put it into a bottle tightly corked, and it may be used the next day. Observe, if more than the quantity prescribed of pearlash should be used, it will deaden and sully the color.
Chemic for green, as above for blue is made by only adding one-fourth more of the oil of vitriol.
_To Discharge Colors._
The dyers generally put all colored silks which are to be discharged, into a copper in which 1/2 a lb. or 1 lb. of white soap has been dissolved. They are then boiled off, and when the copper begins to be too full of color, the silks are taken out and rinsed in warm water. In the interim a fresh solution of soap is to be added to the copper, and then proceed as before till all the color is discharged. For those colors that are wanted to be effectually discharged, such as greys, cinnamons, etc., when soap does not do, tartar must be used. For slate colors, greenish drabs, olive drabs, etc., oil of vitriol in warm water must he used; if other colors, alum must be boiled in the copper, then cooled down and the silks entered and boiled off, recollecting to rinse them before they are again dyed. A small quantity of muriatic acid, diluted in warm water, must be used to discharge some fast colors; the goods must be afterwards well rinsed in warm and cold water to prevent any injury to the stalk.
_To Discharge Cinnamons, Grays, etc., when Dyed Too Full._
Take some tartar, pounded in a mortar, sift it into a bucket, then pour over it some boiling water. The silks, etc., may then be run through the cleanest of this liquor, which will discharge the color; but if the dye does not take on again evenly, more tartar may be added, and the goods run through as before.
_To Re-Dye or Change the Color of Garments, etc._
The change of color depends upon the ingredients with which the garments have been dyed. Sometimes when these have been well cleaned, more dyeing stuff must be added, which will afford the color intended; and sometimes the color already on the cloth must be discharged and the article redyed
Every color in nature will dye black, whether blue, yellow, red, or brown, and black will always dye black again. All colors will take the same color again which they already possess, and blues can be made green or black; green may be made brown, and brown green, and every color on re-dyeing will take a darker tint than at first.
Yellows, browns, and blues, are not easily discharged; maroons, reds of some kinds, olives, etc. may be discharged.
For maroons, a small quantity of alum may be boiled in a copper, and when it is dissolved, put in the goods, keep them boiling, and probably in a few minutes, enough of it will be discharged to take the color intended.
Olives, grays, etc., are discharged by putting in 2 or 3 tablespoonfuls, more or less, of oil of vitriol; then put in the garment, etc., and boil, and it will become white. If chemic green, either alum, pearlash, or soap will discharge it off to the yellow; this yellow may mostly be boiled off with soap, if it has received a preparation for taking the chemic blue. Muriatic acid used at a hand heat will discharge most colors. A black may be dyed maroon, claret, green, or a dark brown; and it often happens that black is dyed claret, green, or dark brown, but green is the principal color into which black is changed.
_To Alum Silks._
Silk should be alumed cold, for when it is alumed hot, it is deprived of a great part of its lustre. The alum liquor should always be strong for silks, as they take the dye more readily afterwards.
_To Dye Silk Blue._
Silk is dyed light blue by a ferment of 6 parts of bran, 6 of indigo, 6 of potassa, and 1 of madder. To dye it of a dark blue, it must previously receive what is called a ground-color; a red dyestuff, called archil, is used for this purpose.
A mordant is prepared of nitrate of iron, 1 pt.; 8 oz. of bichloride of tin crystals, 1/2 oz. of oil of vitriol, and 10 galls. of water. Another liquid is prepared by dissolving 4 oz. of red or yellow prussiate of potash, according to the shade desired. The silks are to be alternately handled in these for 10 minutes, 6 times. After each handling they are washed in cream of tartar water.
_To Dye Cotton and Linen Blue._
Cotton and linen are dyed blue by a solution of 1 part of indigo, 1 part of green sulphate of iron, and 2 parts of quicklime.
The principal coloring matters for dyeing yellow, are weld, fustic, and quercitron bark. Yellow coloring matters have too weak an affinity for cloth, to produce permanent colors without the use of mordants. Cloth, therefore, before it is dyed yellow, is always prepared by soaking it in alumina. Oxide of tin is sometimes used when very fine yellows are wanting. Tan is often employed as subsidiary to alumina, and in order to fix it more copiously on cotton and linen. Tartar is also used as an auxiliary, to brighten the color; and muriate of soda, sulphate of lime, and even sulphate of iron, to render the shade deeper. The yellow dye by means of fustic is more permanent, but not so beautiful as that given by weld, or quercitron. As it is permanent, and not much injured by acids, it is often used in dyeing compound colors, where a yellow is required. The mordant is alumina. When the mordant is oxide of iron, fustic dyes a good permanent drab color. Weld and quercitron bark yield nearly the same kind of color; but the bark yields coloring matter in greater abundance and is cheaper than weld. The method of using each of these dye-stuffs is nearly the same.
_To Dye Woollens Yellow._
Wool may be dyed yellow by the following process; let it be boiled for an hour, or more, with above 1-6 of its weight of alum, dissolved in a sufficient quantity of water as a mordant. It is then to be plunged, without being rinsed, into a bath of warm water, containing as much quercitron bark as equals the weight of the alum employed as a mordant. The cloth is to be turned through the boiling liquid, till it has acquired the intended color. Then, a quantity of clean powdered chalk, equal to the 100th part of the weight of the cloth, is to be stirred in, and the operation of dyeing continued for 8 or 10 minutes longer. By this method a pretty deep and lively yellow may be given.
For very bright orange, or golden yellow, it is necessary to use the oxide of tin as a mordant. For producing bright golden yellows, some alum must be added along with the tin. To give the yellow a delicate green shade, tartar must be added in different proportions, according to the shade.
_To Dye Silks Yellow._
Silk may be dyed of different shades of yellow, either by weld or quercitron bark, but the last is the cheapest of the two. The proportion should be from 1 to 2 parts of bark, to 12 parts of silk, according to the shade. The bark, tied up in a bag, should be put in the dyeing vessel, whilst the water which it contains is cold, and when it has acquired the heat of about 100, the silk, having been previously alumed, should be dipped in, and continued, till it has assumed the wished-for color. When the shade is required to be deep, a little chalk or pearlash should be added towards the end of the operation. Silk and wool may be dyed a fine yellow by picric acid; 15 1/2 grains will color 2 lbs. of silk. No mordant is necessary. Various shades may be obtained by using solutions of different strength.
_To Dye Cottons and Linens Yellow._
The mordant should be acetate of alumina, prepared by dissolving 1 part of acetate of lead, and 3 parts of alum, in a sufficient quantity of water. This solution should be heated to the temperature of 100, the cloth should be soaked in it for 2 hours, then wrung out and dried. The soaking may be repeated, and the cloth again dried as before. It is then to be barely wetted with lime-water, and afterwards dried. The soaking in the acetate of alumina may be again repeated; and if the shade of yellow is required to be very bright and durable, the alternate wetting with lime-water and soaking in the mordant may be repeated 3 or 4 times.
The dying-bath is prepared by putting 12 or 18 parts of quercitron bark (according to the depth of the shade required), tied up in a bag, into a sufficient quantity of cold water. Into this bath the cloth is to be put, and turned in it for an hour, while its temperature is gradually raised to about 120. It is then to be brought to a boiling heat, and the cloth allowed to remain in it only for a few minutes. If it is kept long at a boiling heat, the yellow acquires a shade of brown.
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