According to Linda Knutson's Synthetic Dyes for Natural Fibers, acid dyes fall into several classes: 1, leveling acid or strong acid dye, 2, milling or weak acid dyes, and 3, super milling or fast acid or neutral acid dyes. Leveling Acid Dyes have been sold under the trade names of Kiton, Erio, Intracid, Sandolan, and Amacid, among others; …