An etching is made on a metal plate. The plate is cleaned and de-greased and then warmed and coated with a very thin layer of wax – called a ‘ground’.
Using a needle or similar pointed tool the design is drawn into the ground to expose the metal plate below. The plate is then immersed in an acid bath which ‘bites’ the plate where the metal has been exposed. To create tonal variations the plate is dusted with rosin to create an ‘aquatint’ which is again immersed in acid.
The ground is cleaned off and the plate is then ready to be inked and printed.
Non-toxic developments in Etching
The etching is made on a metal plate as before but the ‘ground’ is replaced with any number of non-toxic acrylic based compounds.
The drawing techniques used to expose areas of the metal plate are the same as for traditional etching. However, the finished plate is immersed in a chemical solution that is less noxious than the acid traditionally used. For example, a copper plate is immersed in ferric chloride and an aluminium plate in copper sulphate.
The cleaning and printing process is the same but the cleaning solutions are once again non-toxic and the inks used are more often water based to reduce the overall impact on the environment.