Acid Dyes are concentrated, powdered, hot water dyes that produce the most vibrant possible results on protein fibers including silk, wool, cashmere, alpaca, feathers, and nylon. But most importantly, the colors are beautiful, pure, transparent and real enough to dive into. Extremely brilliant and colorfast, these dyes are very easy to use and produce a uniform dye job. A half ounce bottle will color up to two pounds of fiber depending on the depth of shade. They can also be used for block and screen printing.