The brown-tone pigment print process was discovered by Robert by applying a special varnish to the original pigment prints. This varnish deepens the contrast and gives a two-dimensional feel to the print. It is also considered to be a unique process in that each print made from the original negative will be different. These differences bring excitement and originality back into the printing process when older negatives are reprinted. These images are also available in Robert Hansen's fine art book Mexican Color