Portret van Didericus Hermannus van Rossum 1793 - 1795

Hendrik Roosing made this portrait of Didericus Hermannus van Rossum using the technique of etching. This is a printmaking process that relies on acid to corrode the unprotected parts of a metal surface to create a design. The plate would have been carefully prepared, covered with a waxy, acid-resistant ground. Roosing would have then scratched the image into the ground with a pointed tool, exposing the metal beneath. The plate was then immersed in acid, which bit into the exposed lines. The depth and darkness of the lines in the print would be controlled by the amount of time the plate spent in the acid, and the strength of the acid itself. This allowed for a range of tones and textures. After etching, the plate would have been inked, wiped clean, leaving ink only in the etched grooves, and then printed onto paper under high pressure. The fine lines and detailed shading evident are testament to Roosing's skill. Considering the labor involved, we can see the value placed on skillful printmaking during this period.