1) Etching

Etching depends on acid to engrave the plate. A protective coating of resin is laid onto the plate (most likely copper) and a line pushed with a steel point through the coating to expose the metal. The plate is then engraved by immersion in acid. Protected by the resin, only the exposed metal of the drawing is etched, and after the protective coating is washed away, ink lies in the etched areas. Etching is very fine, and the technique can produce the most delicate effects. It was often applied before other techniques in mixed-method engravings.

Etching by Leopold Lowenstam of Lawrence Alma-Tadema's 'Quiet Pets', Maas Gallery, £850

2) Wood cut

A wood cut is a ‘relief process’, meaning the printer’s ink lies upon the ridges left by what is cut away from a wood block, as opposed to a wood engraving, whereby ink lies in the grooves cut into the block.

19th-Century Woodcut, John Lambe alias Dr Lambe, Sulis Fine Art, £11

3) Line engraving

Line engravings were made by working directly onto the plate with a burin ­– a small v-shaped chisel. The harder the tool is applied, the deeper it cuts, the more ink the groove holds, and the heavier it prints. Line engraving can produce very clean and draughtsman-like engravings.

 Line Engraving by William Holman Hunt, ‘The Finding of the Saviour’, Maas Gallery, £1,200

4) Mezzotint

The subtlest technique of engraving to produce tone is mezzotint (Italian: ‘half’ and ’tone’). It is virtually the only technique that allows the engraver to work from dark to light instead of from light to dark. Mezzotints are made by completely or partially covering the plate with thousands of very fine dents, applied with a steel tool called a rocker. An image is then created by scraping out the dents completely for white, and burnishing down the burr for tone. Very fine graduations of tone can be achieved by rubbing with a soft cloth. Mezzotint can produce rich and soft engravings of great subtlety.

 Mezzotint by Charles W Campbell of Edward Burne-Jones’ ‘Pan and Psyche’, Maas Gallery, £4,200

5) Photogravure

This method, as with etching, depends on acid to engrave the plate. In photogravure, the same basic technique was employed photographically but instead of resin, a light-sensitive gelatine was used to coat the plate. A photograph was taken of a painting, and light was shone through the negative to expose the gelatine on the plate. Where the light reached the gelatine, it hardened. The remaining soft gelatine was then washed off the plate, leaving the light-exposed hard areas still protecting the plate. The plate was then etched with acid and an image of the painting was printed from it. Photogravures varied enormously in quality. The best photogravures were made in Germany, where the best optics were available.

 Photogravure, ‘A Venetian Fruit Girl’, Sulis Fine Art, £50

 6) Lithograph

Lithography is a ‘surface process’. To make a Victorian lithograph, an image was drawn or transferred onto a piece of flat stone in a hydrophobic medium of wax, oil or resin. A watery solution of gum arabic and weak acid was painted onto the stone, lying only where not protected by the waxy image. A thin layer of hydrophilic solution was left in the porous stone, repelling oil-based ink that would only adhere to the hydrophobic medium, and so the image was transferred to the paper.

Lithograph of ‘Jerusalem From The Mount Of Olives’ by David Roberts, sold by Darnley Fine Art, £1,500

7) Platinotype

A platinotype is a form of photograph perfected to the degree of facsimile by engraver Frederick Hollyer when photographing drawings. The paper was impregnated with light-sensitive compounds of iron. After exposure through a negative, a fine layer of platinum was deposited on the exposed areas by means of a chemical reaction. The temperature when the reaction took place determined the colour of the image. If cold, the colour became a soft, rich black. Hot, and the image tended towards sepia.

 Platinotype of ‘Love Triumphant’ by Frederick Hollyer after George Frederick Watts, Maas Gallery, £150