Mark and France Scully make ambrotypes and albumen prints, both 19th-century processes. A selection of their photographs made by the ambrotype process will be on exhibit at The Spectrum Gallery, 439 Monroe Ave., Rochester. An artists' reception will be held from 5 until 9 p.m. on Friday, April 5, at the gallery. Ambrotypes are a wet-plate collodion process made in-camera. Unlike modern photographs, the areas of silver in these images are light colored, a property inherent to the collodion process. They are processed with a ferrous sulfate developer and fixed with potassium cyanide. The exhibit will be on display through May 26. Spectrum Gallery is open from 9 a.m. until 6 p.m. Monday through Friday, and from 10 a.m. until 4 p.m. on Saturday.