55, ANCIENT POMPEII WALL PAINTINGS FRESCOES 1905 D'Espouy Architecture Art Print

This way the gelatin relief sticks to the copperplate, which now is etched in an iron chlorine solution. In the places where the gelatin film is the thinnest, the places which were most intensively exposed in the step described precedently, the etching is the strongest; correspondingly in the places which were better protected by the gelatin the etching is less.