An indirect engraving technique to create areas with different tones. It is generally used in combination with other techniques like etching or . First of all, the plate is covered with resin; afterwards, the areas the artist does not want to be bitten by acid are covered, generally with varnish or lightbulb lacquer. This process is carried out progressively, depending on the desired tones: the areas which are to be dark will be exposed to the acid for longer. The plate is then submerged in a soft acid, that dissolves the surface in the uncovered areas; these steps are repeated as often as necessary until achieving the desired tones. Once this process is finalized, the plate is cleaned –with alcohol if the material used is resin or wax, with petrol if varnish was used and with acetone is lightbulb lacquer was used. The plate is then inked and the paper is prepared by submerging it in water before printing.

an indirect techniqueof chalcographic engraving. The metal plate is first covered with a protective varnish, on which the engraver draws with an etching needle, ensuring that it touches the surface of the metal plate without producing any furrows. Once the drawing has been made on the varnished surface, the plate is submerged in a diluted acid bath which acts on the exposed metal parts from which the varnish has been removed by the etching needle. Once the lines have been etched, and the plate is taken out of the acid and the remaining varnish removed using a soft cloth and alcohol, it is ready to be inked up and pressed.