Chrome-Tanned Leather: Schultz's Two-Bath Process, 1884

A cleaned hide soaked in potassium dichromate, then in sodium thiosulfate with a little hydrochloric acid, turns into soft, strong chrome leather: the second bath turns the chromium inside the skin into the salt that tans it (Schultz, US 291,784, 1884). A thin skin takes about 15 minutes in each bath, a full skin about an hour. The picture: our drawing of the two baths.