Columbia subject headings:
Harvard subject headings:
Autotype process printing--Congresses.
Illustrated periodicals--Congresses.
Journalism, Pictorial--Congresses.
Newspapers--Illustrations--Congresses.
Photoengraving--Halftone process--Congresses.
Photography--Printing processes--Congresses.
Photojournalism--Congresses.
Photomechanical processes--Congresses.
Postcards--Congresses.
Princeton subject headings:
Autotype process printing--Congresses.
Illustrated periodicals--Congresses.
Journalism, Pictorial--Congresses.
Newspapers--Illustrations--Congresses.
Photoengraving--Halftone process--Congresses.
Photojournalism--Congresses.
Photomechanical processes--Congresses.
Postcards--Congresses.