Etching is a form of intaglio printmaking. Intaglio printmaking includes etching, engraving, drypoint and aquatint. In all of these processes, the image to be printed is incised into the surface or plate. This is different from relief printmaking, where the image to be printed is raised from the surface. With intaglio printmaking techniques, printing is achieved by adding ink to the plate (matrix), then gently wiping away excess ink from the surface. This allows ink to be left in the incisions.
Moist paper is placed on top of the prepared plate and ran through a press with the proper pressure. The ink is pulled up onto the moist paper, producing the print. Intaglio prints can easily be identified by the embossing that occurs around the printed image on the printing paper.
Etching in particular uses acid to "bite" into the metal surface. This makes etching different from engraving. With engraving, the incisions are made by scratching directly into the plate without the aid of an acid "bite".
The process begins by preparing the plate for the ground material. You may choose to bevel the edges of the plate so that it will not tear the paper or damage the press. The plates used for etching are usually made of copper or zinc.
In the demonstration video below, I am using a zinc plate. Next, the ground solution is added to the surface. You may add the solution to the plate with a brush. Allow ample time for the ground to dry. This may take several hours.
When the ground is dry, you may use sharp tools to scratch into the ground. You will be removing areas of the ground in this process. The areas that you remove will be the areas that accept the ink during printing.
Once you have scratched out your image, you will need to gather your acid supplies. Be sure to have eye protection and gloves. Drop the prepared plate into the acid bath to allow the acid to "bite" into the plate.
The strength of the acid will determine the length of time that the plate will need to sit in the acid. As the acid "bites" into the surface, bubbles may be produced. Wipe the bubbles away with a soft brush or a feather.
Remove the plate from the acid and remove the ground with acetone or paint thinner. Now, add ink to the plate. This is best achieved by using a card to work the ink into the grooves of the plate.
Once the plate is covered, gently wipe away the excess ink with cheese cloth or newspaper. Place the prepared etched plate onto a printing press and place dampened water on top of it. Run the plate and paper through the press at an even speed. Pull back the corner of the paper to reveal your etching print.