By Lothar Osterburg
The technique I describe, teach and practise is the original 19th century Carl Klic / Fox Talbot photogravure process, utilizing a dustgrain aquatint.
Photogravure is a true continuous tone photographic etching process. The tonalities are created by an ink layer, gradually varying in depth, with a very fine aquatint (unetched islands of approximately equal size ) to hold the ink. This is achieved by etching the plate gradually from the deepest shadows to the brightest highlights. This way the photogravure is capable of producing a much wider range of tones than any other photographic process, from a deep velvety black to sensitive, bright highlights. Paul Strand considered photogravure perfectly suited for his work because of the technique's capacity to achieve the almost infinite tonal values which lie beyond the human hand. The finished plate is printed, as an etching, on a high quality paper. The ink is a stiff oil based etching ink of any tone or color. The result is an archival continuous tone photographic print on a paper of the artist's choice with the plate mark embossed, giving the final print an almost three-dimensional quality. However, the technical difficulties of this process can seem equally infinite at times. Ansel Adams once said that photogravure was a beautiful technique, but he would not recommend that anyone do it.