Photogravure is an intaglio printmaking technique. It is one of the earliest and most beautiful ways of transferring a photographic image to a piece of paper.
The defining characteristic of a photogravure print is that it has thick layers of ink in the dark areas and very thin layers in the light areas, giving it a very long and rich range of greys and blacks. In the traditional photogravure process the image is exposed onto a light sensitive gelatine carbon tissue and the exposed gelatine is then transferred to a copper plate with an aquatint on it. The plate is then etched in a series of acid baths of decreasing strength creating a plate with deep indentations in the dark areas and shallower ones in the lighter areas.
Around 1980 industrial photosensitive polymer plates came on the market. They were made for relief printing, but soon printmakers realised that when used for intaglio printing they had the same printing characteristics as classic photogravure plates.
BORCH Editions have been working with photogravure since the early 1990s in order to accommodate contemporary artists’ desire to include photographic material into their work. Since 2000 we have only used the polymer plates.
To make a polymer photogravure a film with a positive image is exposed onto a photosensitive polymer plate. The grains in the image cast microscopic shadows into the plate’s surface while the rest of the plate hardens with the exposure. When the plate is washed out with water the unexposed shadows dissolve and form microscopic indentations called cups. Depending on their depth, these indentations hold different amounts of ink during the printing process, allowing for a more extensive colour gradation than any other printing technique.