The lines of the frames of the structure in the portraits can be used to illustrate just how irregular lines on artworks resulting from etching can be. Despite the fact that the structure is supposed to have some uniformity in terms of thickness of lines, this is not the case for this portrait.
Portraits made from etching also make sure that there are some parts of the art materials that are not reached by the ink. This is because of the ground,which is acid resistant. The surfaces of the metal that are covered by ground are not eroded. In the portrait it can be seen that there is a significant portion of the portrait that are unaffected by the ink. This implies that they are the areas that came into contact with the parts of the metal that were covered by the ground, thus unaffected when the whole metal was dipped into acid. The color of texture and color of these areas are exactly the same as the texture and color on the paper on which the art was