The Woodburytype process was developed by Walter Bentley Woodbury (b. 1834, d. 1885) based on a series of patents from 1864. The process sits between being photographic and photo-mechanical; it can be thought of as producing carbon prints mechanically, on an industrial scale. It is a continuous-tone process, no screen or ground is used.

A relief image, from a photographic negative, was produced in bichromated gelatine, this was placed in contact with a lead block and subjected to considerable pressure in an hydraulic press. The result was a lead mould varying in depth in proportion to the tonal areas of the original subject. Pigmented gelatin was placed in the mould and transferred to paper using a press. The Woodburytype produced a continuous tone image consisting of varying depths of gelatine, as no screen or ground was required the result was indistinguishable from a carbon print. The gelatine relief could be re-used to produce further lead moulds.

Woodburytypes were normally printed on thick paper or card, they could be produced in any colour but most often they were in a sepia tone that resembled a photograph, an extra coating of gelatine or similar was often applied to the finished print. Due to the pressure needed to create the mould the images tended to be small. Woodburytypes were most suitable for high-quality reproductions and were typically used for book illustrations, cartes de visite and also lantern slides. By the 1890s its use in book illustration was declining as processes such as photogravure proved more economic.

The origins of photogravure can be traced to W.H.F. Talbot's work in the 1850s, his patents are general in nature covering photo-engraving but include the use of bichromated gelatine which forms part of the photogravure process.¹ Bichromated gelatine was a light-sensitive substance used to transfer the original image to the printing plate and provide a resist to the etching fluid. This was the first use of bichromated gelatine, Talbot also introduced the use of screens to breakup the image.² Photogravure was developed into a commercially workable process by Klíč in 1879 and was known as the Talbot-Klíč process. At first the process was worked with flat-bed presses, later Klíč developed a process suitable for rotary presses (known as rotogravure). Photogravure was used as a general term encompassing rotogravure prints.

Photogravure is an intaglio process, that is, the ink lies below the surface of the etched plate. Its important characteristic is that ink is retained in small pockets of varying depth that deposit varying quantities of ink on the print. To achieve this a screen or irregular aquatint ground is used to divide the image on the printing plate into either a fine grid pattern or, when an aquatint ground is used, minute irregular areas.³

Prints have great tonal range with a soft velvety look to the shadow areas. They are often printed in brown or sepia ink and can be difficult to distinguish from a real photograph.

The process uses a sensitive layer of bichromated gelatine that is treated with heat and water, this causes the gelatine to swell and form random microscopic reticulations across its surface, it is these that hold ink and allow mid-tones to be reproduced. When exposed under a negative the parts of the reticulated surface affected by light (shadow areas) harden and become water repellent, the unexposed regions remain receptive to water. Prior to inking the surface is treated with a water/glycerine mixture, the water is repelled by the exposed areas which will then take-up ink, the unexposed areas will hold water and reject ink.

This was a hand-coloured half-tone process printed from lithographic plates.

The working details of the process remained secret but it seems that a black & white print was hand-coloured, this was then photographed through coloured filters and masks to produce colour separation negatives, one for each colour used at the colouring stage (possibly several partly coloured prints were photographed). These were then printed onto lithographic plates, after being rolled-up with the appropriate colour ink they were printed successively to give the final print. A half-tone screen was introduced somewhere in the process.

The process was developed at the firm of Füssli in Switzerland but licensed to other printers, it was most popular during the 1890s.