Etching - several light/dark gradations
The starting material for an aquatint etching is a metal plate, usually made of zinc or copper. This plate is degreased, coated with powdered resin = Rosin or asphalt is dusted and carefully heated from below so that the resin grains on the plate melt. Covering with masking varnish takes place before each subsequent etching process. This creates a screen grain on the plate. Different shades of grey are achieved by etching the plate several times and covering it more and more each time. With each subsequent covering and etching process, a darker halftone (grayscale) is added. The ink adheres to the depressions of the printing plate during printing, with the ink absorption being determined by the fineness of the screen grain, its density and the depth of the etching .