Toronto. We have all heard or read about the famous processes by Daguerre and Fox Talbot that first opened up the art of photography. I thought many other names in that fine art may be of interest as well. One such name is that of Sir John Herschel. If you did your own development of B&W film or paper, before they faded from popularity, you likely used his invention!
He was photographed (click the icon in the upper left) by Julia Margret Cameron, famous in her own right for her photographic portraits. In 1819, while doing scientific studies independent of the main stream inventors of photography, Sir John discovered that sodium thiosulfate, or hyposulphite of soda as he erroneously called it, would dissolve silver halides better than a salt bath – and hypo or fixer was born.
When Daguerre and Fox Talbot announced their processes in 1839, Sir John wrote to both gentlemen and suggested they use hypo instead of a salt bath. Daguerre adopted hypo immediately. Fox Talbot dragged his heels for two years but finally adopted hypo in his process as well.