AIC-PMG Winter Meeting 2025

In May 1839, Mungo Ponton, a Scotsman, reported on the light sensitivity of dichromate salts and described a photographic method based on dichromate salts, stating that the process offered a cheap substitution for silver. There are very few examples of his process that exist. There was almost no discussion of Ponton’s process, until Alphonse Poitevan and others began using dichromates in carbon printing and photomechanical printing. Indeed some histories erroneously cite Ponton as the an inventor of photomechanical printing. This paper is a discussion of Ponton’s process with an example of his process from 1840 and a discussion of why examples are rare. It includes analysis of photogenic drawings made using Ponton’s method, as well as a consideration of what might appear as fading is actually a transition to stability.