Woodbury’s process underwent several improvements subsequent to the original patent. In its final form, a hardened colourless ‘gelatine relief’ (i.e. a carbon print minus the carbon) was impressed upon a block of lead under enormous hydraulic pressure-an idea doubtless taken from Auer’s nature printing’. The intaglio mould thus produced was placed in a hand-press, and warm pigmented spread over this, the press closed, and the excess gelatine hardening in an alum bath. The resulting picture was similar in appearance to a Swan carbon print. consisted of coloured gelatine in relief, the thickest parts being the darkest.
Woodbury claimed that 600 to 800 impressions could be obtained from each metal mould, and about twenty moulds made from one gelatine relief- that is, at least 12,000 impressions could be obtained from one relief.17 In practice, however, it was found that only five or six metal moulds could be made from one gelatine relief.is The prints could be made at the rate of 120 an hour. 19 In 1867 Goupil & Co. of Paris acquired for 150,000 francs (then XAooo) the Woodbury type patent rights for France, where the process was introduced as ‘Photoglyptie’. In 1870 the American rights were acquired by John Carbutt of Philadelphia. Gernsheim 264