The London Encyclopædia: Part II. The Practise of Dyeing. Of Dyeing Black.

The London Encyclopædia: Part II. The Practise of Dyeing. Of Dyeing Black.


Kappale teoksesta:

The London Encyclopædia, or Universal Dictionary of Science, Art, Literature, And Practical Mechanics, Comprising A Popular View of The Present State of Knowledge.

By The Original Editor of The Encyclopædia Metropolitana, Assisted By Eminent Professional And Other Gentlemen.

In Twenty-Two Volumes

Vol. VII

London:
Printed For Thomas Tegg, 73, Cheapside;
R. Griffin & Co., Glasgow; Tegg and Co., Dublin; Also J. & S. A. Tegg, Sydney and Hobart Town.

1839

Part II. The Practise of Dyeing. Of Dyeing Black.
s. 596-598



OF DYEING BLACK.

118. We now proceed to give an account of the most usedul and advantageous processes for dying different colors, and begin with the method of dying black.

It has been justly observed, by an able writer on this subject, that absolute black being a complete privation of all color, can scarcely be ascribed to any body in nature, since it must then become invisible. The color so named, as communicated by dye-stuffs, is, indeed, rather an intense blue or brown, and is generally produced by the union of these coloring matters with a ferruginous mordant, and hence it may not improperly be termed a compound color. The juise of the cashew nut communicates a black that will not wash out, and which resists boiling with soap or alkalis. The anacardium occidentale and the toxicodendron afford a durable dye, but it is of a brownish hue. The juice of the sloe affords a pale tint of a brownish cast, which becomes deeper after having been repeatedly washed with soap, and afterwards wetted with a solution of alkali. On boiling sloes, their juice becomes red, and the red tinge, which in that state it imparts to linen, is converted by washing with soap into a bluish color of some durability. But these methods of obtaining a black color cannot be employed in dyeing, because these substances are not to be obtained in sufficient quantity, and the black which they afford is not equal to that formed by the common processes. All black colors, therefore, are the effects of combination. To produce them, the black particles formed by the union of the astringent principle with the oxide of iron, held in solution by an acid, are fixed on the stuff that is intended to be dyed.

119. There are very few substances which have the property of producing of themselves a permanent black color. The juice of some plants is found to produce this effect on cotton and linen.

120. When the particles are precipitated from the mixture of an astringent and a solution of iron, they have only a blue color; if they be then left exposed to the air, and moistened with water, their color becomes deeper, but still the blue is distinguishable. The stuff itself then contributes to increase the intensity of the black, whethet it be that in this state of combination it undergoes a slight combustion, or that the coloring particles undergo a further degree of combustion, from presenting a larger surface to the air. Without the action of the air, however, a fine black cannot be produced; on which account the operations are performed at different intervals, during which the stuff is taken out of the bath, that it may be exposed to the air. M. Berthollet has ascertained, that black stuffs placed in contact with pure air diminish its volume, and consequentrly absorb a certain portion of it.

121. Of Dyeing Woollen Black. - Referointi suomeksi Hellot'n kuvaamasta prosessista:
100 osaa värjättävää ainetta
10 osaa sinipuuta
10 osaa jauhettuja väriomenoita
Sinipuu ja väriomenat laitetaan pussiin ja keitetään 12 tuntia riittävässä määrässä vettä.
Kolmasosa liemestä laitetaan toiseen asiaan, johon lisätään 2 osaa espanjanvihreää. Värjättävää ainetta liotetaan tässä jatkuvasti sekoittaen kaksi tuntia, liemi pidetään kuumana, mutta ei saa kiehua. Kahden tunnin kuluttua värjättävä aine nostetaan pois.
Kolmasosa liemestä laitetaan toiseen astiaan, johon lisätään 2 osaa rautasulfaattia. Tulen annetaan hiipua ja liemen annetaan jäähtyä puoli tuntia, koko ajan sekoittaen.
Loput liemestä lisätään tähän ja väriaineita sisältävä pussia puristellaan voimakkaasti. 15-20 osaa sumakkia lisätään ja leimen lämpötila nostetaan kiehumispisteeseen, sitä kiehautetaan nopeasti ja kiehuminen pysätytetään pienellä määrällä kylmää vettä. 2 osaa rautasulfaattia lisätään, jonka jälkeen värjättävää ainetta pidetään liemessä tunti, jonka jälkeen se otetaan ulos, pestään ja tuuletetaan, jonka jälkeen se laitetaan astiaan uudelleen ja sekoitetaan jatkuvasti tunnin ajan.
Mustaa väriä pehmennetään ja kiinnitetään väriresedasta tehdyllä liemellä, joka jäähdytetään lyhyen kiehumisen jälkeen ja värjättävä aine huuhtaistaan siinä.From the process described by Hellot, woollen cloth, to be dyed black ought to receive the deepest blue tint, or mazarine blue, to be washed in the river as soon as taken out of the vat, and afterwards cleansed by the fulling mill.

For every hundred pounds of stuff, ten pounds of logwood, and ten pounds of galls reduced to powder, are put into a bag, and boiled with a sufficient quantity of water, for twelve hours. A third of this liquor is put into another copper, with two pounds of verdigris. The stuff is im-

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mersed in this, and continually stirred for two hours. The liquor should be kept hot, but it ought not to boil. At the end of two hours the stuff is taken out, and a similar portion of the liquor is put into the copper, with eight pounds of sulphate of iron. During the solution of the copperas, the fire is diminished, and the liquor is allowed to cool for half an hour, stirring it well the whole time. The remainder is then to be added, and, after making this addition, the bag containing the astringent matters should be strongly pressed, to separate the whole. A quantity of sumach, from fifteen to twenty pounds, is now to be added, and the liquor is just raised to the boiling temperature; and when it has given one boil, it is to be immediately stopped with a little cold water. A fresh quantity of sulphate of iron, to the amount of two pounds, is then added, and the stuff is kept in it for another hour, after which it is taken out, washed and aired; it is again put into the copper, and constantly stirred for an hour. It is then carried to the river, well washed, and fulled. To soften the black color, and make it more firm, another liquor is prepared with weld. This is made to boil for a moment, and when it is cooled the stuff is passed through it. By this process, which is indeed somewhat complicated, a beautiful black color is produced.

122. But the methods usually followed dyeing black, are more simple. Cloth, which has been previously dyed blue, is merely boiled in a vat of galls for two hours. It is then kept two hours, but without boiling, in the vat of logwood and sulphate of iron, and afterwards washed and fulled. According to Hellot's process, a liquor is to be prepared a pound and a half of yellow wood, five pounds of logwood, and ten pounds of sumach, for every fifteen yards of deep blue cloth; and, the cloth having boiled in this for three hours, ten pounds of sulphate of iron are added; the cloth is allowed to remain for two hours longer, when it is taken out and aired, after which it is again returned to the vat for an hour, and then washed and fulled.

When stuffs are to be dyed at less expense, instead of the blue ground, a brown or root-colored ground may be substituted. This brown or fawn color is communicated by means of the root of the walnut-tree, or green walnut-peels. The sutffs are then to be dyed black, according to some of the methods already described.

Referointi suomeksi: englantilaisten värjäreiden käyttämät suhteet ovat:
100 osaa syvän siniseksi värjättyä vaatetta
5 osaa rautasulfaattia
5 osaa väriomenoita
30 osaa sinipuuta.
Vaate ensin käsitellään väriomenoilla, sitten liotetaan sinipuuliuoksessa, johon on lisätty rautasulfaattia.123. The proportions of the ingredients employed by the English dyers are, for every hundred pounds of cloth previously dyed a deep blue, about five pounds of sulphate of iron, five pounds of galls, and thirty of logwood. The first step in the process is to gall the cloth, after which it is passed through a decoction of logwood, to which the sulphate of iron has been added.

124. As a substitute for galls, the leaves of the arbutus, uva ursi, have been recommended and employed. The leaves must be carefully dried, so that the green color may be preserved; 100 pounds of wool are boiled with sixteen pounds of sulphate of iron, and eight of tartar, for two hours; the following day the cloth is to be rinsed as after aluming; 150 pounds of the leaves are then to be boiled for [...] water, and after being taken out, [...]tity of madder is to be added [...] putting in the cloth at the same time [...] to remain about an hour and a half [...] taken out and rinsed in water. By [...] it is said, that blue cloth receives [...] good black, but white cloth becomes [...] deep brown.

125. After the operations for dy[...] have been finished, it is washed in [...] fulled, till the water funs off colorles [...] are recommended by some in fulling [...] hut is rather difficult to free the [...] from the soap. After the clot has [...] fulling mill, some propose ti [...] bath of weld, by which it is said [...] and the color better fixed; but [...] Lewis, this operation, which in [...] advantage, is useless after the cl[...] treated with the soap suds.

126. Of Dyeing Silk Black. - In [...] a black color to silk, different [...] necessary, such as boiling, galling, [...] vat, dyeing, and softening. To [...] shade of silk, it is necessary to [...] gummy substance of which we [...] spoken. This is done by boiling [...] hours with one-fift of its weight [...] and afterwards beetling and [...] it. The gummy substance, before [...] which silk in its natural state cont[...] increase the strenght of the silk, [...] called rawM but renders it more [...] out, from the stiffness it imparts to [...] raw silk takes a black color with [...] than silk which has been scoured [...] gum, that black is much less [...] the re-actives calculated to dissolv[...] matter, in a much less forcible [...].

127. In the process of galling [...] fourths of its weight of galls are tro [...] three or four hours, but the propor[...] depend on their quality. After the [...]liquoe is allowed to remain at rest for [...] the silk is then put into the bath, [...] from twelve to thirty-six hours, [...] taken out, and washed in the river. [...] is capable of combining with a [...] of the astringent principle, or tan, [...] receives a considerable increase of [...] allowed to remain for a longer or [...] the silk is required to have more or less [...] weight. Hence to communicate to [...] called a heavy black, it is allowed [...] longer in the gall-liquor; the process [...] oftener, and the silk is dipped [...] great number of times.

128. While silk is preparing [...] of dyeing, the vat is to be heated, [...] occasionally stirred, that the [...] to the bottom may not acquire [...]. It should always be kept under the [...]perature. Gum and solution of [...] in different proportions, according [...]ent processes. Then the fum in [...] the liquor near the boiling temperature [...] to settle for about an hour, The [...] general is previously divided [...]

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that each may be succissively put into the vat, is now immersed in it. Each part is then to be three times wrung, and after each wringing, hung up to air. The silk, being thus exposed to the action of the air, acquires a deeper shade. This operation being finished, the bath is again heated, with the addition of gum and sulphate of iron, and this is repeated two or three times, according as the black rewuired is light or heavy. When the process is finished, the silk is rinsed in a vessel with some cold water, by turning or shaking it over.

129. Silk, after it has been taken out of the dye, is extremely harsh, to remove which it is subjected to the operation of softening. A solution of four or five pounds of soap for every 100 pounds of silk, is poured through a cloth into a vessel of water. The solution being completed, the silk is immersed, and allowed to remain in it for about fifteen minutes; it is then to be wrung out and dried.

130. When raw silk is to be dyed, that which [...] a natural yellow color is preferred. The galling operation must be performed in the cold, if it be desired to preserve the whole of the gum, and the elasticity which it gives to the silk; but if part only of it is wished to be preserved, the galling is to be performed in the warm vat.

131. The dyeing is also performed in the cold. All that is necessary is to add the sulphate of iron to the water in which the stuff is rinsed. By this simple process, the black dye is comminucated. It is then washed, beetlet once or twice, and dried without wringing, that its elasticity may not be destroyed. Raw silk may be dyed by a more speedy process. After galling, it may be turned or shaken over in the cold bath; and thus by alternately dipping and airing the stuff, the operation may be completed. It is then to be washed and dried as before.

132. The method of dyeing velvet at Genoa, which has been simplified and improved in France, is thus described by Macquer. For every 100 pounds of silk, twenty pounds of Aleppo galls, reduced to powder, are boiled in a sufficient quantity of water for an hour. The bath is allowed to settle till the galls have fallen to the bottom; they are then taken out, and two pounds and a half of sulphuric acid, twelve pounds of iron filings, and twenty pounds of gum, are put into a copper, pierced with holes in all directions. This vessel is suspended by means of two rods passed through the handles, in the boiler, but so as not to touch the bottom. The gum is left for an hour to dissolve, but must be stirred occasionally. If after this time the gum has not all left the pierced copper, it is a proof that the liquor is saturated with it; but if, on the contrary, the whole has disappeared, from two to four pounds more may be added. This cullender should remain constantly suspended in the boiler, except when the dyeing is going on, during which time it must be removed. During these operations the boiler must be kept hot, but not allowed to boil. The galling of the silk is performed with one-third of its weight of Aleppo galls. The silk is allowed to remain in the liquor for six hours the forst time; then for twelve; and for the rest, secundum artem.

133. Dr. Lewis remarks, that though white silk may be dyed a good black, without using either logwood or verdigris, the addition of those two ingredients contributes greatly to improve the color both in silk and in wool. But as the great use of galls in dyeing silk black renders it very expensive, it is of consequence to find some method of diminishing their quantity. M. Anglès proposes the following process: - When the silk has been carefully boiled and washed in the river, it is to be immersed in a strong decoction of green walnut-peels, and left in it till the color of the bath is exhausted. It is then taken out, slightly wrung, dried, and washed in the river. The decoction of walnut-peels is made by boiling a full quarter of an hour, when it is taken from the fire, and suffered to subside before dipping the silk, which has been previously immersed in warm water. A blue ground is next given by means of logwood and verdigris. For every pound of silk, an ounce of verdigris is dissolved in cold water: the silk is left in this solution two hours; it is then dipped in a strong decoction of logwood, wrung out slightly, and dried before it is washed at the river. For light blacks, galling may be altogether omitted; but for a heavy black, half a pound of galls must be employed for every pound of silk intended to be dyed. To prepare the liquor, two pounds of galls and three of sumach are macerated in twenty-five gallons of water over a slow fire, for twelve hours. After straining, three pounds of sulphate of iron, and as much gum arabic are dissolved in it. In this solution the silk is dipped at two different times, leacing it in two hours each time, taking care to air it after the first dipping, and to dry it before giving the second fire, when it is to be again aired and dried: it is then beetled twice at the river; after which a third fire is given it, in the same manner as before, except that it is left in the liquor four or five hours. When drained and dried, it is again beetlet twice at the river. The heat during the operation must not exceed 120° of Fahrenheit's thermometer; and before the last two fires, an addition of half a pound of sulphate of iron and as much gum arabic is to be made.

For removing the harsness that silk acquires from the black dye, M. Anglès proposes that a decoction of weld should be preferred to a solution of soap; and observes that if silk be dyed blue with indigo, previous to its being dipped for black, it will take only a mealy black, but that a velvety black will be obtained, if it be prepared with logwood and verdigris; and that green walnut-peels soften the silk.

134. Of Dyeing Cotton and Linen Black - To impart to cotton and linen a deep black dye that will resist the action of soap, is attended with considerable difficulty. Several methods have been proposed as improvements on the old process; the following, practised at Rouen, is thus described by M. d'Apligny. The stuffs are first dyed sky-blue in the usual manner, and are then wrung out and dried. After this they are galled for about twenty-four hours, allowing four ounces

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of galls [...], they are then [...] and well dried.

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