The first stage of etching involves preparing the metal plate. Copper, steel, aluminum or zinc plates are most commonly used. The artist sands one side of the plate with sandpaper of different grit, depending on the desired effect. A fine grit sandpaper makes a fine surface; a coarse grit sandpaper makes a textured background. The artist cleans the plate with turpentine to remove any fingerprints.
The artist uses etching ground or varnish to cover both sides of the plate. This material protects the metal from the chemicals during the etching process. The artist makes the design on one side of the metal plate using a sharp tool such as a burin or a needle. The drawing uncovers areas of the metal which are exposed to chemical treatment. The drawing is reversed when printed on the paper.
Etching is performed using a bath of acids, such as nitric acid, hydrochloric acid or ferric chloride. The metal plate is immersed in the acid. The longer the plate is held in acid, the coarser the lines of the etching. Electrolytic etching is an alternative to etching with acids. This method doesn't require the use of toxic substances, but instead, an additional metal plate is needed. The second plate is made of the same metal as the plate that contains the design. The plates are placed in the electrolysis solution, which is a bath of sulphates (e.g., zinc sulphate if the artist uses zinc plates or copper sulphate if copper plates are used). The metal plate with the design is connected to the positive terminal of a direct power source (e.g., a car battery), while the other plate is connected to the negative terminal. The chemical reaction in the solution creates a caustic effect on the plate that is etched.
After removing the plate from the acid or chemical solution, the artist cleans both sides of the plate. Printing ink is spread on the side that contains the design, making sure that the thick ink covers all the corroded paths. Any excess ink is wiped off. The artist dips the paper that is about to be printed in water and places it in between two clean sheets of tissue paper, which absorb the moisture. The paper and the metal plate are pressed together through a roller press. The metal plate may be treated with different colored inks to craete variations of the same print.