Acid dyes are used to color silk, wool, feathers, other protein fibers and nylons, and nothing does it better! Extremely brilliant and colorfast, they are highly concentrated, powdered hot water dyes that produce level, uniform color during immersion dyeing. They exhaust well and wont bleed or fade with washing. Acid dyes are known to produce the most luscious colors of all. In addition to yarn, fiber and fabric dyeing, Jacquard Acid Dyes may also be used for direct painting or printing applications, using steam setting. Dont be alarmed by the name-the only acid involved is the white vinegar or citric acid that you add to the dye bath. This package contains Jacquard Acid Dye- Jet Black, One Pound. Made in the USA.