"Drawing on his deep understanding of musical theory, he adapted the language of sound to explain subtle variations of light. From this discovery of the similarities between these physical phenomena he developed in the 1930s his famous Zone System in an attempt to devise a standard procedure for exposure and development that would give consistent negative quality. "The black and white picture known as The Black Sun is one o f your best-known ones. Tell me how you came to take it. I was working in the desert east of the Sierra Nevada a little after sunrise. I wanted to black and white photograph right into the sun, planning to use the brilliant flare as part of the composition. I made several exposures with a 5 x 7 camera and Isopan black and white film; I intended to develop one in Kodak D-23.I knew I might get a little reversal - a phenomenon of excessive exposure - in this negative, and as the sun disc appeared to have slightly less density in the centre of the general flare I decided to develop the next negative in Pyrocatechin, a highly compensating developer. In this negative the disc of the sun was almost fully reversed and has black and white printed very dark. Reversal can be a very exciting effect when it's properly used. I don't think that its physical chemistry is yet completely understood. Actually 'The Black Sun' is not a good description of this black and white picture any more, because it now means the equivalent of a neutron star, and that's an astronomical phenomenon which had not been discovered at the time I made the black and white picture. But I guess the title will stick!" (source- and I'm guessing it is generally from 'Examples- The Making of 40 Photographs')
