A 500 year old printmaking tradition still going strong…
The basic principle. A waxbased, acid-resistant etching ground is applied to a polished, degreased metal plate. Typically of copper or zinc, the plate is then held upside down and, using lit wax tapers, the ground is heat-sealed and blackened with soot. The black soot provides contrast when an image is drawn through the ground to reveal the raw metal underneath using an etching needle.
The back and edges of the plate are then covered with an acid-resistant varnish and allowed to dry. Alternatively, adhesive packing tape can be used to protect the back of the plate. The plate is then placed in a bath of etching solution, whereupon only the exposed linework of the drawing is chemically etched. The longer the plate remains in the solution, the deeper these lines will be be etched; deeper lines hold more ink and result in darker, stronger lines when the plate is subsequently printed.
This characteristic can be put to good creative use. Masking out certain lines (which are to remain lighter etched) with a acid-resistant stop-out varnish, the plate is again placed in the bath for further etching, resulting in contrasting lighter and darker printing lines. This is the basis of line etching which is often combined with other techniques such as aquatint, drypoint or engraving.
After the etching process, the plate is thoroughly cleaned before applying ink. A stiff ink is dragged across the plate and forced into the linework with the help of a piece of card. The excess ink is wiped off using pads of 'scrim', a type of wide mesh gauze. Once the inked-up plate is placed on the etching press bed, a sheet of pre-dampened paper is laid on top and then covered by a number of press blankets. The inked-up plate is now ready to be rolled – under enormous pressure – through the press.
After printing, the still-damp paper with wet ink needs to be gradually dried out flat, using absorbent blotting paper and/or boards under weight.