Photogravure

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Photogravure is a type of intaglio printmaking developed in the 1830s by Henry Talbot in England and Nicephone Niepce in France. These were the first photographs, pre-dating daguerrotypes and the later silver-gelatin photos. Photogravure was used for both original fine art prints and for reproduction of works from other media such as paintings. Photogravure is distinguished from rotogravure in that photogravure uses a flat copperplate etched rather deeply and printed by hand, while in rotogravure, as the name implies, a rotary cylinder is only lightly etched, and is a factory printing process for newspapers, magazines, and packaging. Due to an unfortunate confusion of terms, searches for "photogravure" on the web often turn up industrial machinery designed for rotogravure.

Photogravure registers an extraordinary variety of tones, through the transfer of etching ink from an etched copperplate 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. Unlike half-tone processes which merely vary the size of dots, the actual quantity and depth of ink in a photogravure etching are varied. Photogravure practitioners such as Peter Henry Emerson and others brought the art to a very high standard of expression in the late 19th century, which continued with the work of Edward Steichen in the early 20th century. But the speed and convenience of silver-gelatin photography eventually displaced photogravure, which fell into disuse after the Curtis gravures in the 1920s. Fifty years later, photogravure experienced a revival in the hands of Aperture and Jon Goodman, who studied it in Europe. Photogravure is now actively practiced in several dozen workshops around the world.

[edit] Engraving

A film positive is made from the original photographic negative. This positive is placed on top of a photo-sensitive gelatin tissue, and the sandwich exposed to ultraviolet (UV) light. A separate exposure to a very fine photographic screen is made, or alternatively an aquatint grain of asphaltum or rosin is applied and fused to the copperplate. The UV light travels through the positive, hardening the gelatin in proportion to the degree of light exposed to it. The gelatin tissue is adhered to or "laid down" onto the copper plate. A hot water bath allows the tissue backing to be removed and then washes away the soft gelatin in relation to the exposure, forming a resist on the copper plate. The plate is etched in a bath of ferric chloride. The etch corrodes the copperplate in relation to the thickness of the gelatin. Thus the image gets etched onto the copperplate by the ferric chloride, creating a gravure plate. The pattern formed by the aquatint grain or the screen exposure creates minute 'lands' around which the etching occurs, giving the copperplate the "tooth" to hold ink.

[edit] Printing

Ink is applied to the surface of the plate with a brayer or tamper. The plate is then wiped with tarlatans, removing excess ink and leaving ink only in the recesses. The plate is then run through a press with a sheet of dampened paper, and the ink transfers from the recesses of the plate into the paper, creating the impression.

[edit] External links

• The Art of The Photogravure: Process, History and Examples
• Jon Goodman Photogravure
• http://www.kamprint.com Examples of photogravure etchings, history and technical description of the process, guidance on framing and collecting.
• Description of photogravure
• Polymer gravure process
• http://www.curtis-collection.com/process.html

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