AQUATINT
Aquatint is capable of creating a wide tonal range and can add significant depth to an image. The effect can be similar in appearance to a watercolour wash. Aquatint can be used on it’s own, or in conjuction with line etching.
Traditionally, the aquatint process uses a resin which is made into a powder and dusted over the plate. This is often done in an aquatint booth. The booth is essentially a large wooden box containing a paddle operated from outside. As the handle is turned the paddle rotates, disturbing the powder resting at the bottom of the box and sending millions of fine particles into the air. The plate is placed inside the aquatint booth for a few minutes as these particles fall back down. When the plate is removed it should have a fine dusting of the powder on the surface.
The aqautint powder is very easily disturbed at this point and must be set onto the plate. The underside of the plate is heated - this causes the aquatint particle to liquify into lots of tiny globules which solidify as they cool. These tiny dots now form an acid-resist.
If the plate was immersed in acid at this stage the areas that are not protected with aquatint would etch to the same depth, hold the same amount of ink, and create the appearance of a single tone when printed. To produce varying tonality, and create interesting marks and gradations, areas of the plate must be painted with an acid-resistant varnish.
The plate is then bitten in stages, with areas on the plate stopped out before being etched further. Any sections painted with varnish before the first etch will print white, with the other areas becoming progressively darker the longer they have been left in the acid before being painted over.