Etching is a traditional printing process used by artists such as Durer and Rembrandt, and it has changed very little over the centuries. A metal plate (zinc or copper) is first heated and then coated with a ground - a mixture of beeswax, bitumen and resin. The design is then drawn into the ground using an etching point or a similar tool - even nails can be used! The design will be printed in reverse, so any letters or numbers must be drawn backwards.
When the design is complete, the whole plate is put into an acid solution. The metal that has been exposed by the drawn lines is bitten by the acid. Bubbles which form while the acid is working are brushed off by a goose feather to allow further exposure. The longer the plate is in the acid, the stronger and deeper are the resulting lines. Other processes such as aqua-tinting can also be used at this stage to give extra texture, and parts of the plate can be stopped out with varnish to retain very fine lines. When the bite is complete, the plate is removed from the acid, rinsed thoroughly and then the ground is removed with white spirit.
The plate now has the drawing etched into it and is ready to be printed. Ink is applied to the plate and then rubbed off, leaving the etched lines filled with ink. The plate is covered with a piece of damp etching paper and put through a press - which resembles a large mangle! The pressure pushes the paper down over the plate and squeezes the ink from the grooves onto the paper and lastly the paper is carefully peeled back to reveal the finished etching.
Because each print has to be individually inked and printed they may vary slightly.