Columbia subject headings:
Photographic chemistry--History--Sources--Exhibitions.
Photography--Printing processes--History--Sources--Exhibitions.
Victoria and Albert Museum--Photograph collections--Exhibitions.
Harvard subject headings:
Photographic chemistry--History--Sources--Exhibitions.
Photography--Printing processes
Photography--Printing processes--History--Sources--Exhibitions.
Photography--Processing
Victoria and Albert Museum--Photograph collections--Exhibitions.
Princeton subject headings:
Photographic chemistry.