How Do You Draw With Metal? Prepare the Paper So It Bites

A pointed rod of soft metal is drawn across a surface that has been coated with a ground containing an abrasive, typically bone ash or powdered chalk bound in glue. The ground scrapes minute particles of metal off the point and holds them, leaving a line. Plain paper will not work, since it is too smooth to abrade the metal and nothing is deposited. The mark is extremely fine and consistent, and cannot be made darker by pressing harder, so tone is built entirely by hatching more lines closer together.

The constraints are severe and they shaped how artists worked:

• •No erasing, since the mark is embedded in the ground
• •No variation in darkness from pressure
• •Tone built only by density of hatching
• •A prepared surface, made in advance and in batches
• •Planning, because a misplaced line stays visible
• •A very fine point, resharpened constantly

Several metals work and one behaves in a way that made it preferred. Lead leaves a grey mark that stays grey. Copper leaves a warmer line. Silver leaves a pale cool grey that oxidises over weeks and months into a warm brown, so a drawing changes colour after the artist has finished it and continues to deepen for years. Renaissance artists knew this and worked with the eventual tone in mind rather than the one in front of them, which is a striking thing to ask of a draughtsman. The surviving drawings are therefore darker now than when they were made.

The ground is made rather than bought and its preparation is half the craft. A paste of powdered bone ash or chalk, sometimes with white pigment, is mixed with a weak glue or gum and brushed onto paper or prepared board in several thin coats, each allowed to dry and lightly smoothed before the next. Too little abrasive and the stylus slides without depositing anything. Too much and the surface is gritty and tears the paper. Pigment can be added to tint the ground, and Renaissance examples on pink, grey and blue grounds survive, with white heightening applied on top.

The technique was standard for preparatory drawing across fifteenth century Europe and was used by Leonardo, Durer, Raphael and van Eyck, partly because nothing better existed. Graphite deposits discovered in Cumbria in the sixteenth century produced a material that marked plain paper, varied with pressure and could be erased, and the older method was abandoned almost completely within a century. It survived as a specialist discipline, revived by nineteenth century artists interested in Renaissance practice, and is still taught, largely because the impossibility of correction forces a kind of attention that other media allow one to avoid.

A metal stylus leaves a line only on a ground containing an abrasive that scrapes particles off the point, so plain paper does not work. The mark cannot be erased or darkened by pressure, so tone comes from hatching alone. Silver oxidises from cool grey to warm brown over months, so Renaissance artists worked towards a tone they could not yet see.