Italian
English
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| photogravure | |
| From MINIPRINT
Bitumen heliogravure 5.6 x 10.5 cm. - 2008 |
| héliogravure | |
| The matrix of photogravure
(héliogravure au grain, photoaquatint) – the most sophisticated
among the photomechanical processes – is made of a copper plate
prepared, grained and etched in the same way as in the technique of
aquatint. The only difference is that the transfer of the image onto the plate occurs photographically instead that manually using proper tools as needles, burnisher, burin, roulette, … . To obtain the printing matrix we will start from any negative film or modern digital file and produce a positive film fit to the process regard tonal range, density and size of the final print. Through this film we will impress a gelatinized and sensitized ‘carbon tissue’ that - dampened and placed face down onto the surface of the polished plate - transfers a jelly image on it. This operation may be done before or after the ‘graining’ of the metallic surface, that means covering the plate with bitumen fine dust in a dust-box and melting it in a oven. The jelly, with it different thickness in lights and shadows, and the bitumen even grain, are the ‘resist’ for the acid. The etching (with ferric chloride solutions) to obtain the very rich intaglio, is driven visually, looking at the biting of a known densities’ step wedge, side to the plate. You need at least 4 baths at different concentration of etching salt, to win the different thickness of the gelatine layer. As well as having a great but non-appreciated expressive autonomy, the photogravure may be useful for mixed technique works. The job is laborious and few words are non sufficient to give the delicacy of the operations, but the result is of great visual impact. Héliogravure is based on both dimension and depth of the sign it produces and is still one of the finest means of photoreproduction we had as heritage from the end of XIX century experimentations. The matrix – on which it’s possible to use the classical tools of the traditional engraving, is inked and printed by hand on suitable presses. |
| Photogravure Photogravure Dichromated gum Carbon process Kallitype Cyanotype Silver print Toning BLACKHOLES heliogravure 2006 WITH-DRAWN heliogravure 2001 Questioni di Stile |
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| www.miphotography.com.au |  Rivista digitale di informazionesulla stampa d'arte. |