AQUATINT

The aquatint is an indirect process of engraving and can be considered a technical variant on etching, as the engraving is made with an acid.

It follows the same procedure as the one described for etching, but the final effects, obtained with a porous plate, are similar to water-colours. The texture is created by dropping grains of bitumen onto a hot plate, which melt and stick to the surface, forming a more or less thick ground.

Aquatint is a tone process rather than a line method : instead of forming an image with an organised series of lines, it creates areas of controlled shapes and contrasts.

To do so, the matrix is specially treated to obtain a rough surface able to hold the ink. This roughness is called granulation.

The picture shows the procedure of traditional granulation.

The biting operates in the hollow spaces. The longer the biting time, the darker the background, thus achieving different nuances of gray simply by varying the time of immersion.

A wonderful example:

 (from "tecniche dell'incisione originale" INClub Firenze)