Jacquard Acid Dyes Jacquard Acid Dyes produce the most vibrant colors possible on protein fibers and nylon. These concentrated, powdered, hot water dyes are the best dyes available for silk, wool, cashmere, alpaca, feathers, and nylon. 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. Don't be alarmed by the name, the only acid involved is vinegar.