The primary means Goya used to create linear work in his prints was etching, a process that involves drawing on a copperplate with a needle. A range of etching needles, sharpened to varying degrees, would have helped him manipulate the width and depth of lines scratched through the ground into the surface of the copperplate. The process was designed to expose the underlying copper so it would be vulnerable to the action of the acid, which would bite into the surface, accentuating any lines that had been created with the needle.
Acid was applied by either pouring acid over the face of the plate as it stood slightly angled in a tray or making a wall of ‘banking’ or ‘bordering’ wax (a combination of wax and resin) around the perimeter of the plate, turning the plate into a bath the acid was poured into34 (See figs. 7 and 8). The background tone in No hay quien nos desate? (Is there no one to untie us?) is not uniform with the right side of the print appearing darker than the left. This effect is likely to have been achieved by using the ‘banking’ or ‘bordering’ wax method of applying acid, with Goya tilting the plate so the acid gathered on the upper right corner, biting this area for longer. (See fig. 26).
When examining Ni más ni menos (Neither more nor less), etched lines in the donkey’s ears can be identified by studying the shape of their ends which are blunt rather than pointed. (See figs. 9 and 10).
When working on the plate for Origen de los arpones ó banderillas, (Origin of the harpoons or banderillas), Goya exposed the etched lines of the matador’s jacket and areas of the bull for an extended period, causing some of the lines to be eaten away completely. (See figs. 11 and 12). This is referred to as over-biting and it creates a wide, textured area that can hold ink. It is often unintentional and is caused by accidentally exposing the plate to acid for too long or using strong acid that is hard to control. Several of Goya’s plates may have been damaged irretrievably by over-biting and these are only known from rare or unique working proofs.34