Vandyke brown printing, a derivative of iron-silver print processes (argentotypes) from 1842, takes its name from the color cast of final print, a deep brown similar to popular paint pigment, Vandyke brown. Like many of photography’s earlier processes, VDB is a contact printing process needing ultraviolet(UV) light to make the exposure onto a piece of coated paper.
Van Dyke brown prints should last as long as any other silver process.