Dye classes more commonly used on cellulose (cotton etc.)
The same types of fiber reactive dyes that are the best of all dyes on cotton and other cellulose fibers, including Procion MX, Cibacron F/Sabracron F, and Drimarene K, among others, can also be used as acid dyes to dye wool. An acid dye recipe must be used,
with vinegar or other acid replacing the soda ash (base) used in dyeing cotton.
As with all acid dyes, boiling or heat-setting of some sort is generally
required. (PROchem's recipes include one which uses black
plastic bags to absorb heat from the sun for this purpose.)
For recipes, use any acid dye recipe, or see:
We never use the soda ash reactive dye recipe for dyeing wool, because the high pH can be quite damaging to wool fiber. However, silk, although protein, is not a hair-based fiber, and it tolerates soda ash quite well. You can dye silk with soda ash at room temperature, or with vinegar plus heat, equally well.
Color shifts from one fiber to another
Even when following the identical recipe, fiber reactive dyes mixtures, such as black, may yield quite different colors
on protein fibers than they do on cotton and other cellulose
fibers. Do not use black Procion MX dye mixture if what you want is
black silk. (It may yield other very interesting and lovely colors, however.)
The reason for this is that some of the dyes in the mixture may work better on one fiber than another, to a greater or lesser extent, so a dye mixture must be prepared differently for each different fiber.
However, the pure dye colors appear to produce identical hues regardless of the fiber on which they are used. If you wish to make matching items using different fibers, stick to the pure unmixed single hue fiber reactive dyes. (I maintain a list of the different single-hue Procion MX type dyes from various suppliers.)
Fiber reactive dyes designed for protein fibers
Some of the Lanaset dyes, also known as Sabraset or Telana dyes, are actually fiber reactive dyes which are designed for use on wool, rather than cotton. They are used at an acid pH. See Lanaset dyes.
Are you trying to get black?
It is generally agreed that the best dye to use to make black on silk, wool, or nylon is the Lanaset Black. There is no concern about color shifts, and the black produced is very rich and dark. Fiber reactive dyes tend to be smaller molecules, producing brighter colors, and may be less effective at producing a very dark color.
Vinyl sulfone dyes
This discussion would not be complete without a mention of the fact that the vinyl sulfone dyes (Remazol dyes) can be used as true fiber reactive dyes on wool, which means that they attach via very strong covalent bonds, stronger than the bonds that hold acid dyes to the fiber. One recipe requires simmering the wool in a dyebath with vinyl sulfone dyes for forty-five minutes. See Vinyl Sulfone Fiber Reactive Dyes.