Argyrotype is an alternative photographic process similar to the Van Dyke process. It uses silver and iron salts to create sepia-toned photographs. The images produced are durable and resist aging well, making it a popular choice for photographic artworks. Argyrotype uses a chemical solution of ferric iron and silver sulfonate applied to paper. Let's see how to make it !
Ref: Mike Ware, British Journal of Photography, 139, (6824), 17-19 (13 June 1991) . https://www.mikeware.co.uk/mikeware/Argyrotype_Process.html