The London Encyclopædia: Part II. The Practise of Dyeing. Of Dyeing Gray.
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
Printed For Thomas Tegg, 73, Cheapside;
R. Griffin & Co., Glasgow; Tegg and Co., Dublin; Also J. & S. A. Tegg, Sydney and Hobart Town.
Part II. The Practise of Dyeing. Of Dyeing Gray.
OF DYEING GRAY.
138. Gray color are properly [...] dark [...] from the deepest to the lightest. They may be produced in several ways; the [...] are the most approved [...].
In the first method a [...] and a solution of sulphate of [...] These ingredients must be prepared [...] then a part of it added to a [...] water of a sufficient degree of of [...] , and [...] to be dipped.
When it has attained the shade [...] out, more of the [...] must be added to the same bath. cloth is dipped, to give it a deeper shade [...] same [...] deepest shades, always adding [...] the liquors: though, for black-gray and [...] deep shades, it is best to give the cloth [...] a blue ground, more or less deep [...] circumstances.
139. The second process for dyeing gray, [...] which is, by Hellot and others, preferred [...] in consequence of the stuff [...] of galls more firmly, [...] quantity of powdered galls as may [...] in enclosed in a linen [...] in water for two hours. In [...] stuffs must be boiled for an hour and [...] out. Some solution of iron is the [...]
liquor, and the stuff passed through it, so as to produce a light shade; more solution of iron is then to be added to produce a deeper shade, and so on till the stuff acquire the requisite color.
If in this operation we go beyond the mark, the color must be darkened as before; but repeating these operations is prejudicial to the stuff, so that we should endeavour to catch the proper shade at once, by taking it occasionally out of the bath. Care must be taken that the bath do not boil, and that it be rather warm than too hot.
In whatever manner grays are dyed, they should be immediately washed in a large body of water, and the darkest may even require soap to cleanse them. It is sometimes required to give grays a tint of another color, as a nut, agate, or reddish cast. In this case, having given a tint more or less blue according to the object intended, the stuffs are dipped in the remains of some cochineal liquor, that has served for dyeing either scarlet or violet, adding galls, logwood, madder, &c.; they are then browned for more or less deep with a solution of iron. For the nut gray, yellow wood and logwood are added to the galls, and the stuff is to be dyed from white.
140. Silk takes all grays, except black-gray, without previous aluming. The bath is composed of fustic, logwood, archil, and sulphate of iron. These ingredients are varied according to the tint to be given. Thus more archil is employed for grays that are to have a reddish cast, more fustic for those that should incline to a russet or green, and more logwood for those that are to be of a darker gray. For iron-gray logwood and solution of iron are only employed. But black-gray requires alumin; after which the silk is taken to the river, and then dipped in the weld bath. A part of this bath is thrown away, and its place supplied with logwood liquor. When the silk is impregnated with this, a sufficient quantity of solution of iron is added, and, as soon as it has acquired the proper shade, it is to be washed and wrung carefully. If the gray should happen to be too dark, the silk is dipped in a solution of tartar, and afterwards in warm water; and, if by these means the color be weakened too much, the silk is again dipped in a bath of dye that is quite fresh.
141. Linen and Cotton should have a blue ground imparted to them for black-gray, iron-gray, and slate-gray, but for no other. All the shades require a galling proportionate to have the gray to be produced. Gall baths that have before served for other purposes are often employed. When the stuff has been galled, wrung, and dried, it is dipped in a vessel of cold water, to which is added a proper quantity of the bath from the black cask, and of a decoction of logwood. The stuff is worked in separate portions, and afterwards washed and dried properly. Two other processes for dyeing gray are given by M. Pileur d'Apligny, which, according to him, produce more permanent color. They are these.
1. The yarn is galled, dipped in a very weak bath of the black cask, and then maddered:
2. The yarn is dipped in a very hot solution of tartar, wrung gently and dried. It is then dyed in a decoction of logwood. After this operation it appears black; but, on working it attentively in warm soap suds, the surplus of the dye is discharged, and it remains of a durable slate gray.
142. A process, says M. Berthollet, the success of which is known to us, consists in taking a very diluted solution of acetate of iron (it is sufficient to add a little of this acetate to a quantity of water), and a decoction of sumach, also very dilute. The cotton is passed in succession from one liquor to the other, till the eished for shade be attained. The finish is given by passing through a water slightly acidulated by sulphuric acid, otherwise the sumach gives a russet hue. By the same process may be obtained with nutgalls less lively grays; and the alder bark affords an agreeable one, which borders on hazel.
A skilful manufacturer of Rouen has communicated to us the following provess, which he makes use of successfully for cotton velvets. A galling is given with an equal quantity of gallnuts and logwood, after which a bath of cold water is administered, and next another bath of water, in which there has been dissolved ea weight of sulphate of iron, equal to one-half of the preceding ingredients. After working the cotton about a quarter of an hour in this bath, it is rinsed in cold water, and brightened.
For this purpose a bath of tepid water is used, to which one-eightieth of decoction of weld, and a little alum, are added. The cotton is left about twenty minutes in this bath, after which it is washed in cold water, and dried.
By modifyuing the doses of the ingredients, grays, from pearl-gary to the deepest gray, may be thereby obtained.
For grays on printed goods, the same mordant is impressed as for a clear violet, and sumach or gall-nuts are employed according to the shade that is desired.