What technique is used. To create the shaded areas in Goya’s print asta su abuleo

Printmaking.

Explanation:

After some research, I went to https://artmuseum.princeton.edu/collections/objects/5480

and in the medium section, it showed  aquatint.

According to Wikipedia, "Aquatint is an intaglio printmaking technique, a variant of etching that produces areas of tone rather than lines. For this reason it has mostly been used in conjunction with etching, to give both lines and shaded tone."

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