258 



DYEING. 



.i DT* 



way are not no lively as those which are dyed in fresh 

 baths Miiu-d to the desired shade. 



! I ,t 



Omcrent 



.YCIIOW. 



Procesiof 

 Dr Ban- 



:;il. l.ime favours the extraction of the colouring 

 nutter of weld, and heightens it-, colour, but it renders 

 it more liable to be affected by acid-. Common salt 

 renders it richer and deeper ; -ulphate of lime also 

 deepens it ; alum renders it paler, but more lively ; and 

 tartar still paler. The shades ot'yi How obtained from 

 weld may IK- modified by such additions, by the pro- 

 jKjrtion of the plant, by the length of the process, 

 and by the mordant u<cd in prewiring the stuff. Jv'hcf- 

 fer affirms, tliat by Ixiiling the stuff two hours with 

 a fourth of its weight of solution of tin, and the same 

 of tartar, washing it, mid boiling it fifteen minutes with 

 an equal weight of weld, it will take a fine yellow, 

 which, however, will not pciifhvtc the internal part of 

 the fibre. Pcerner directs the cloth to be prepared in 

 the same manner as for the scarlet dye. 



315. The colour may be modified also by passing the 

 stuff, when it comes out of the weld dye, through 

 another bath. Thus to produce a golden yellow, the 

 cloth, when it is taken out of the welding, may be pass- 

 ed through a slight madder red ; and for a tawny, 

 through a bath made with a little soot. 



3 16. The colouring matter of quercitren affords a 

 yellow dye, which, in every point of view, ought to 

 be regarded as a valuable acquisition to the art of dye- 

 ing. This drug was first introduced to the notice of 

 dyers by Dr Bancroft, who lias given a very full ac- 

 count of its properties and uses. We shall now describe 

 the processes which he has recommended for obtaining 

 from it the various shades of yellow. 



317. The cheapest and most simple method of ap- 

 plying the quercitron colour upon wool," says Dr 

 Bancroft, " is that of boiling up the bark with its 

 weight, or a third more than its weight of alum, in 

 suitable portion of water, for about ten minutes, and 

 then dyeing therein the wool or cloth previously scoured, 

 as before mentioned, taking care to give the higher co- 

 lours first, and the paler straw colours afterwards. In 

 this way yellows not wanted to be very full or bright 

 may be dyed very expeditiously and cheaply ; and they 

 may afterwards be considerably raised and enlivened, 

 by passing the wool or cloth, unrinsed, a few times 

 through hot water, into which a little clean powdered 

 chalk has been previously stirred, in the proportion of 

 about a pound or a pound and a half of chalk for each 

 hundred pounds weight of wool or cloth. The bark 

 when used in dyeing, (being first ground,) should al- 

 ways be tied up in a linen bag, of a loose open texture, 

 and suspended in the dyeing liquor by a cord, with 

 wluch it may be dragged occasionally backwards and 

 forwards through it, to extract and spread the colouring 

 matter more equally." 



318. When a deeper and more permanent colour is 

 to be given, the stuff should be boiled in the ordinary 

 way, but without either tartar or argol, for the space of 

 an hour, or an hour and a quarter, with about one- 

 sixth or one-eighth of its weight of alum dissolved in 

 a suitable quantity of water ; it should then be im- 

 mersed without being rinsed, with 'about as many 

 pounds of powdered bark as there were used of alum 

 to prepare the stuff, and turned as usual through the 

 iMiiling liquor, till it assumes the proper shade. About 

 one pound of clean powdered chalk for every hundred 

 pounds of wool, may then be mixed with the bath, and 

 the boiling continued eight or ten minutes longer, when 

 the yellow will have become both higher and brighter. 



i)rnge jrd- 319. Woollen stuffs may be dyed of a beautiful orange 

 yellow, by the following process. For every hundred 



Piffrrent 

 ttwdc*. 



|xiiiiids of wool or cloth, take ten pounds of quercitron 



and an equal weight of the murio-sulphate of tin ; ''' ' 



let the bark, in the state of ]x>wder, and inclosed in a """ ~~ ' 



bag, be first introduced into the dyeing \cssel, with 



hot water ; six or eight minutes after, add the inurio- 



.-ulphate i if tin to the bath, and stir the whole well for 



two or three minutes ; after which the cloth i- put into 



the dyeing liquor, and turned hii-kly for a few minutes. 



Tlie colouring matter attaches itself so quickly, and at 



the same time so uniformly to the cloth, that after the 



commencement of the l>oiliiig, the highest \cllow may 



be communicated in less than fifteen minutes, without 



the smallest danger of its being UUCMII. 



320. When a very bright golden yellow approach- (., Men yd- 

 ing less to the orange is wanted, Dr Bancroft recoiii- low. 

 mends seven or eight jxmnds of murio-sulphate of tin. 



with alxiut five pound- of alum, and ten jMiunds of 

 bark for every hundred pounds of cloth. The bark 

 is first boiled a few minutes, then the murio-sulphate 

 of tin with the alum in added ; after which the cloth 

 is dyed, as already directed. By using smaller pro- 

 portions of the ingredients, pure bright yellov. 

 less body may be obtained, liaving every variety of 

 shade. 



321. Yellows of a delicate greenish tinge may be Greenish 

 obtained, by employing, in addition to these ingredi- y- - Uw. 

 ents, a quantity of tartar. Thus, for a full bright yel- 

 low, delicately inclining to the greenish tinge, Dr 

 Bancroft advises eight pounds of bark and six pounds 



of murio-sulphate of tin, with six pounds of alum, and 

 four of cream of tartar. A little more alum and tar- 

 tar will render the yellow more delicate, and give it 

 more of the greenish tinge ; and when this clean, live- 

 ly, delicate greenish tinge is de.-ired in the utmost 

 perfection, he recommends these different ingredients 

 to be employed in equal quantity. As the.-c very de- 

 licate shades are not required to possess much fuhu >- 

 or body, ten pounds of bark, and the like quantities of 

 murio-sulphate of tin, alum, and tartar, are quite suf- 

 ficient for dyeing three or four hundred pounds weight 

 of stuffs. 



322. In order to dye these very pale greenish shades Dc i icatri y 

 with exquisite delicacy and beauty, Dr Bancroft re- prcl . n isli 

 commends to boil the bark with a small proportion of ilmdcs of 

 water in a separate tin vessel for the space of six or j i-How. 

 eight minutes, then to add the murio-sulphate of tin, 



alum, and tartar, and boil them altogether for about 

 fifteen minutes ; and afti -rwards put a little of this yel- 

 low liquor into a dyeing vessel, previously supplied with 

 water sufficiently heated. The mixture being proper- 

 ly stirred, the cloth is introduced into it, and dyed as 

 usual ; fresh supplies of the yellow liquor being added 

 as it is needed. In this way, the palest and most de- 

 licate shades may always be dyed with ease and cer- 

 tainty ; and those who have never seen the effects of 

 this process, will hardly, in Dr Bancroft's opinion, con- 

 ceive the exquisite beauty and delicacy of these pale, 

 but lively, greenish lemon yellows. 



323. The colours obtained by these means from Durability 

 quercitron are extremely durable, and are found to of d>e co- 

 resist even the action of strong mineral acids, and of loure - 

 boiling soap-suds, as well as exposure to the air. The 



last they are enabled to withstand by the good effects 

 of the alum, and more especially of tartar. 



324. By employing very small proportions of cochi- Aurora ,. 

 neal with quercitron, and the mordants used in the i our . 

 processes already mentioned, the colour is exalted to a 

 beautiful orange, and even to an aurora. Madder pro- 

 duces the same effect when used with quercitron, but 



in an inferior degree. 



