Mungo Ponton, Scottish photographic pioneer, c 1870-1879.

Mungo Ponton (1801-1880) discovered the light sensitivity of potasium bichromate and was later appointed Vice-President of the Society of Arts for Scotland. His discovery that paper soaked in a solution of potasium bichromate could be a cheap substitute for paper coated with silver salts, was later used in the development of permanent photographic and photomechanical printing proceses.