To dye wool YELLOW.
The proportion of alum used by dyers in these processes varies from one-fourth down to one-twelfth, of tartar one-sixteenth is used, for every pound of cloth. Equal parts of alum and tartar are used for worsted and yarn, each of which (alum and tartar) is only from one-twelfth to one-tenth of the weight of the material to be dyed.
The shades of yellow are straw yellow, pale yellow, lemon yellow, and full yellow.
In order that the cloth should be properly impregnated with the mordants of alum and tartar, according to what is allotted to the shade, whether light or full, it should be boiled in the preparation at least one hour; two hours for a full yellow; then a fresh liquor is to be made to receive the weld, which must be previously boiled: for a full yellow four or five pounds of weld will be required to one pound of cloth or worsted; for the lighter shades less of course: but a sufficient quantity only of weld should be used, and this should be boiled and re-boiled, as it will keep but a very little time after boiling. If you have a gradation of shades you will save drugs and expense by dyeing the fullest shades first, and the lightest last; but by this method the lightest will not be so bright as if they were done first, and the liquor renewed with fresh boiled weld, and so on to the fullest shade. At last you must have for the goods a preparation weak or strong according to the light or full colour of which they are to be. The last dyeing, whether of cloth or yarn, will assuredly take all the colour out of the liquor of any consequence.
While expense is not an object, it is best, not only for yellows, but for all other colours, to have the preparation and the dye proportioned to the shade, the colour done at once, and the remaining liquor thrown away; but as the price usually paid for dyeing will not enable the dyer so to do, he commonly dyes his shades in succession, as above, and with the utmost economy.
To dye wool BROWN, or of a FAWN COLOUR.
These shades are extremely various, and are dyed without any preparation with alder-bark, red sanders, sumach, galls, madder, &c. and under a boiling heat, although it is occasionally necessary to boil some of the ingredients together previous to the dyeing: for instance, red sanders will give its colour out best when boiled with galls, alder-bark, sumach, &c. Cam-wood, bar-wood, walnut rinds, roots, &c. are used in some of these shades, the varieties of which are almost infinite. Practice is required in this branch of dyeing equal to or beyond any other.
To dye wool PURPLE, &c.
Pass the goods through archil, next through the blue vat, with the usual precautions, then through hot water. For some shades they should be alumed, and then dyed with cochineal for the crimson part of the purple. Blue and crimson make purple, violet, &c. according to the patterns required.