Hellot says:—"It is impossible to obtain more than one colour from a mixture of blue and yellow, which is green; but this colour comprehends an infinite variety of shades, the principal of which are the Yellow green, the Light green, the Gay green, the Grass green, the Laurel green, the Molequin green, the Deep green, the Sea green, the Celadon green, the Parrot green, and, I shall add, the Duck-wing green, and the Celadon green with Blue. All these shades and the intermediate ones are made after the same manner and with the same ease. The stuff or wool dyed blue, light or dark, is boiled with Alum and Tartar, as is usually done to make white stuff yellow, and then with Weld, Savory, or Greening Wood. The Weld and the Savory are the two plants that afford the finest greens."
Another old Dye book says:—
"If you would dye your goods green, you must first dye them yellow with Broom or Dyer's Weed, otherwise Yellow Weed; after which put them into the Blue vat."
Every dyer has his particular yellow weed with which he greens his blue dyed stuff. But the best greens are undoubtedly got from weld and fustic.
The wool is dyed first in the blue vat; then washed and dried; then after mordanting dyed in the yellow bath. This method is not arbitrary as some dyers consider a better green is got by dyeing it yellow before the blue. But the first method produces the fastest and brightest greens as the aluming after the blue vat clears the wool of the loose particles of indigo and seems to fix the colour.
If a bright yellow green is wanted, then mordant with alum after the indigo bath; if olive green, then mordant with chrome.
The wool can be dyed blue for green in 3 different ways:—1st. in the indigo vat (see [page 68] et seq.); 2nd. with Indigo Extract (see [pages 65-67]); 3rd. with logwood, the wool having been previously mordanted with chrome (see [p. 82], No. 7, and [p. 85] No. 17). For a good bright green, dye the wool a rather light blue, then wash and dry; green it with a good yellow dye, such as weld or fustic, varying the proportion of each according to the shade of green required. Heather tips, dyer's broom, dock roots, poplar leaves, saw wort are also good yellows for dyeing green. If Indigo Extract is used for the blue, fustic is the best yellow for greening, its colour is less affected by the sulphuric acid than other yellows.
Bancroft gives many recipes for dyeing green with quercitron. He says:—
"Wool which has been first properly dyed blue in the common indigo vat may be made to receive any of the various shades of green which are usually given in this way from weld, by boiling the blue wool (after it has been well rinsed) in water, with about one eighth of its weight in alum, and afterwards dyeing it unrinsed with about the same quantity of Quercitron bark and a little chalk which should be added towards the end of the process.
In the same way cloth that has previously received the proper shade of Saxon blue, may be dyed to a beautiful Saxon green: it will be proper to add about 3 lbs. chalk with 10 to 12 pounds of alum for the preparation liquor for 100 lbs. weight of wool which is to be turned and boiled as usual for about an hour, and then without changing the liquor, 10 or 12 lbs. of Quercitron bark, powdered and tied up in a bag, may be put into it, and the dyeing continued. When the dyeing has continued about 15 minutes, it will be proper to add another lb. of powdered chalk, stirring it well in, and to repeat this addition once, twice or three times at intervals of 6 or 8 minutes. The chalk does not merely answer the purpose of decomposing the acid left in the wool by the sulphate of indigo, but it helps to raise the colour and to render it more durable."