WHAT IS A PHOTOGRAVURE?
and other Photo Intaglio Definitions
The goal of this page is to educate people (including artists, teachers, students, curators, collectors and dealers) to the main differences in the various types of photo intaglio printing processes. It is my hope that people will use the appropriate term when describing the processes or medium of these prints. The public already knows too little about these processes so it is important that they are not further confused or misled when looking at prints or learning a process. Correct terms with alternates are in bold for each category. Fine Art Photo Intaglio Processes Photogravure (see photogravure plates in the photo below)
Photogravure is a process of etching continuous tones into copper with a sensitized gelatin pigment paper resist (aka carbon tissue) using a continuous tone positive and aquatint screen or dustgrain aquatint. The process was invented by William H. F. Talbot and Karl Klic in the late 1800s for archivally reproducing fine photographic prints. They also employed the use of the dustgrain for its organic grain and fine tonal resolution as well as deeper etched shadows. The tones of the positive are etched into the copper plate in the proportion to the density giving a multi depth layer of ink and a very perceivable and virtually infinite range of tones. Careful timing of the different etching baths also adds another way of controlling the tonal curves. This process yields an etched plate that can be retouched and re-worked with any of the traditional etching processes. The copper plate is often electroplated with iron (steel faced) for printing very consistent and/or long editions. This is still the absolute best way to make a photographic intaglio plate for printing. Photogravure is also referred to as 'Gravure' or 'Heliogravure' and 'Heliograbado' in Spanish. When a drawing on mylar is used instead of a photgraphic positive the print is known as a 'Direct Gravure'. Photo Etching
Photo Etching is a process where a zinc or copper plate is coated with a high contrast, negative working photo-sensitive liquid such as KPR or sensitized fish glue or a thin film photopolymer such as Puretch. The coated plate is exposed to a very fine halftone positive or line image. Halftones can be made digitally now with inkjet or laser printers. If an aquatint is required it can be done traditionally with dust or spray, built in digitally or with a screen exposure. The plate is developed with a solvent or mild alkaline producing a high resolution etch resist. This process yields a plate that can be etched to the desired depth and tone. The resist is usually stripped before printing and the etched plate can be retouched and re-worked afterwards with any of the traditional etching processes. A Photo-Etching can also correctly be labeled as simply 'Etching'. Photopolymer
Photopolymer is a non-etch process of making a photo intaglio printing matrix. Plates are either manually coated with a thick photopolymer film such as Imagon or Zacryl or they are available as pre-coated flexographic printing plates. These pre-coated plates are known as Printight by Toyobo and Solarplate. They are either singly exposed with a very fine halftone that has a grain already built into the blacks or they are exposed with a continuous tone positive which requires a separate exposure to an aquatint screen. The plates are developed in water or a mild alkaline solution which washes away the unhardened photopolymer creating fine recessed crevices for the ink. The final print can sometimes appear quite similar to a photogravure print except the process is significantly different and lacks the subtle tonal range of a good gravure, especially dustgrain gravure.
The 'Photopolymer Intaglio' process is often incorrectly referred to as 'Photogravure'. These prints are not 'Photogravure' or 'Gravure'. A 'Photopolymer Intaglio' print is also often called 'Photopolymer Gravure' or 'Polymer Gravure'. The inclusion of the word gravure here is also misleading since there is no etching or engraving involved, there is only developing. 'Photopolymer' is also correctly known as 'Photopolymer Intaglio'. These descriptions can also be used when positives are hand drawn on mylar. A print made with any of the processes above could be called Photo Intaglio or simply Intaglio but when the description is more specific then the term should accurately reflect the process used. Some Related Commercial Printing Processes Rotogravure
Etched rotogravure is very similar to photogravure except a line screen is always used for the grain and the image is etched onto a metal cylinder using the same gelatin pigment paper resist. Now in the US and Europe most rotogravure cylinders are made with computer controlled diamonds or lasers that engrave the various depth cells. Chemically etched rotogravure is still going strong in other parts of the world, especially Asia, India, Mexico and Indonesia. Rotogravure is used where high quality reproduction and/or long run printing is required. National Geographic is printed with rotogravure. Photo engraving
Photo engraving is used in circuit board manufacture, chemical milling of parts, metal relief plates for printing and foil stamping or embossing dies. Pre coated zinc, magnesium or brass plates are used for high volume relief print runs and embossing. Photopolymer films and liquid resists are used to coat these plates. Flexographic Printing
Flexography is a commercial relief printing process that uses a pre-coated flexible photopolymer plate. Varying thicknesses and durometers are available. These plates have been adapted for Photopolymer Intaglio as well as hand printed letterpress. Flexography is a form of rotary web letterpress using flexible photopolymer image carriers and fast-drying inks fed from an anilox inking system. Flexography is the major process used to print packaging materials. The plates are exposed with a halftone negative of about 175 dpi.
©2011Cape Fear Press
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Below: Photogravure plates made in the July 2011 gravure workshop | 
