Photogravure is an intaglio printmaking or photo-mechanical process whereby a copper plate
is grained (adding a pattern to the plate) and then coated with a light-sensitive gelatin tissue
which had been exposed to a film positive, and then etched, resulting in a high quality intaglio
plate that can reproduce detailed continuous tones of a photograph.
Because of its high quality and richness, photogravure was used for both original fine art prints
and for photo-reproduction of works from other media such as paintings.
Photogravure registers a wide variety of tones, through the transfer of etching ink
from an etched copper plate to special dampened paper run through an etching press.
The unique tonal range comes from photogravure's variable depth of etch, that is, the shadows
are etched many times deeper than the highlights