Question

What is silverpoint and when was it first used What are its advantages and disadvantages?

Answer 1

A silverpoint 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 silverpoint lines are very difficult to erase, so fixing mistakes is not an easy task.

Answer 2

A silverpoint 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 silverpoint lines are very difficult to erase, so fixing mistakes is not an easy task.