Page 240 - Summaries of Boccaccio's Decameron: A Visionary Journey in 100 Stories and 100 Etchings by Petru Russu

Etching is traditionally the process of using strong acid to cut into the
unprotected parts of a metal surface to create a design in intaglio in the
metal creating sunken areas which hold the ink. (Petru Rusu in 13 / 04 / 1986
intaglio printmaking the 100 Days of Decameron on H. Fleury printing press
manufactured in Paris in the 1880s.)