UREA (Ammonium carbamate): White granules, alkali mordant and modifier. Organic nitrogen excreted in urine, used so early there is no record, precipitated circa 1173 AD, synthesized in 1828. Solvent and humectant; helps keep fiber wet long enough for dye to penetrate. Indigo vat moisturizer. Best on cellulose fibers. Use with sodium alginate thickener when painting or directly applying Procion dye for super intense color.