A platinum test fragment from the printing of Penn’s photograph of an English coal man. Taken in London in September 1950, Penn revisited the Small Trades series for printing in the platinum-palladium process in the late 1960s. After brushing a solution of light sensitive platinum and palladium salts onto watercolor paper, Penn exposed the sheet for 30 minutes.
From his decades of platinum printing, Penn retained test fragments like this one that he found visually interesting. Test strips are commonly used in darkroom printing to test and perfect the coating and exposure before making a print on a full sheet of paper. The rich tones Penn achieved in platinum-palladium and the visible brushstrokes from the coating imbue the test fragments with an unusual beauty, as if segments of his iconic images have been conjured on the paper.