Note 23 — Paper 61
Reading edition
O Op. cit., pp. 46-48. Knowledge of the process seems to have disappeared completely during the 18th and 19th centuries. Hubert Herkomer, writing in 1892, believed that he had invented the white ground for the first time (Etching and Mezzotint Engraving, London, 1892, pp. 4 and 25).