Citric Acid Crystals: In crystal or powder form this is an odourless substitute for white distilled vinegar, when working with acid dyes.
Use approximately 1 teaspoon, pH should be about 4.
PRO WashFast Acid Dyes are designed to permanently dye protein fibres — animal fibres like wool, silk, angora, mohair, alpaca, soy silk, and nylon. These dyes are very concentrated and therefore only require a small amount, ProChem recommends Ammonium Sulphate (for pastel to medium shades) or Citric Acid Crystals (for pastel to dark shades).
One ounces (28 grams) of dye powder will dye 6 pounds (2.72 kilograms) of wool to a medium shade.
PLEASE NOTE: The following colors may not completely exhaust when doing an immersion bath, even after adding more acid at the end of the dyeing: Rhodamine Red 370, Hot Pink 337, Turquoise 478 and Black 672 when dyed at a 5% depth of shade