Answer:
A silver point drawing is used by dragging a silver rod or wire across a surface. This wire is usually called as a primer or gesso. It was used since the late Gothic/early Renaissance era.
Advantage: Renaissance artists used silver and occasionally lead point for preparatory sketches under their paintings and frescoes as well as for studies on paper.
Disadvantage: It is an unforgiving media because silver point lines are very difficult to erase, so fixing mistakes is not an easy task.
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