Sometimes accidentally produced in domestic life by some overdrawn tea remaining on a steel knife.
The modern "lead-pencil" is wrongly named, being made of graphite, which is pure carbon. This does not appear to have been used in mediaeval times.
The vellum was not prepared in any way to receive the silver-point drawing; but when an artist wanted to make a finished study in silver-point he covered his vellum or paper with a priming of fine gesso, powdered marble, or wood-ashes; this gave a more biting surface to the paper, and made the silver rub off more easily and mark much more strongly. In the case of manuscript illuminations a strongly marked line was not needed, as the outline was only intended as a guide to the painter.
See above, pages [29] and [30], on the pens and inkstands of the classical scribes.
Usually meant for Saint Jerome translating or revising the Latin edition of the Bible.