It consisted of treating skins first in a solution of potassium bichromate and hydrochloric acid, followed by a second immersion in sodium thiosulfate solution. Today the use of this two-bath process is limited primarily to kid leather tanning. After suitable pretreatment, the hides are tanned in a solution of basic chrome sulfate prepared by reducing sodium bichromate in the presence of sulfuric acid. Most glove, garment and shoe upper leathers are tanned by this same process today, with the added benefits of modern improvements in processing technology. The production of pigments is an important application of the chromium family of chemicals.
Sodium bichromate is used extensively in the manufacture of lead chromate pigments.
These lead chromates are relatively inert, brilliant, and have excellent covering power. They are widely used in the making of paints, printing inks, paper coloring and floor coverings. The interaction of Sodium Bichromate with lead salts produces lead chromate and yields colors ranging from light yellow to red orange. Blues are made by oxidizing ferrocyanide with sodium bichromate. Adding chrome yellow to this blue yields chrome green.