The following link is to a short film on the work of Richard Samuel Roberts who worked in South Carolina in the 1920's and 1930's. He was self taught and worked during the day at the post office and afterwards as a photographer. Roberts can be considered as an artist and also as a historian of American society of the period. His work survives because he preferred to use glass plates rather then the new nitrate film. Of the estimated 10,000 images he is believed to have taken some 4000 negatives have survived.

http://video.scetv.org/video/2285659557/