34a-b. (a, top) William Blake, Europe a Prophecy copy H, plate 1. Relief etching, 23.4 x 16.7 cm., etched 1794, printed 1795. Typ 6500 41 (A) F, Department of Printing and Graphic Arts, Houghton Library, Harvard College Library. Detail showing that the fine white lines between shallows and relief lines were caused by the inking dabber accidentally depositing ink in the shallows and the paper not picking up the ink from the escarpments between relief plateaus and etched valleys. (b, bottom) William Blake, Europe a Prophecy, plate 1. Relief etching, 23.4 x 16.7 cm., etched 1794, printed c. 1794. Yale Center for British Art, Paul Mellon Collection. Detail of the same section of the plate as illustration 34a, but the shallows of this impression were not accidentally blemished with ink and hence the white line escarpments defined by the blemished and relief areas are absent.