A plentiful supply of paper – just as much as the study of ancient sculpture or single-point perspective – was among the factors that led to what we call the Renaissance. It allowed artists to think and work in different ways, a transformation as significant as the Internet and computer technology have been in the early twenty-first century.

Not, of course, that paper itself was a new material in the fifteenth century. On the contrary, it had first been made in China a millennium and a half previously; but the recent availability of paper was a knock-on effect of another innovation: the invention of moveable type by Johann Gutenberg of Mainz.

By 1450 Gutenberg had set up a commercial printing press, and by the 1460s presses began to be established in Italy. As soon as that happened, there was a greater demand for paper, so more paper mills were built.

The main alternative for drawing had been vellum – scraped and burnished calf-, sheep- or goat-skin – which was luxurious and labour intensive to prepare. The price list of a Florentine stationer’s from the 1470s lists vellum as fourteen times more expensive than paper.

Paper, however, was still quite a costly material. That was why artists often used both sides of a sheet; it was too valuable to waste.

So, after Ghirlandaio had used a piece of paper to work out the composition of The Visitation, one of the frescoes for the Tornabuoni Chapel, in a flurry of rapid pen strokes – establishing the positions of the figures, jotting down the background architecture – the paper was then turned over and used as a cartoon for a piece of classical moulding framing the scenes.

A series of holes was then pricked through, following the lines of the egg and dart and palmette motifs, and charcoal or black chalk dust forced through them to transfer the lines to the wall.

Always acutely cost-conscious, Michelangelo was an especially assiduous recycler of used paper, sometimes searching through the litter in his studio for a useable scrap and coming up with a sheet he had drawn on years before but which still retained some blank space.

As a result, Michelangelo’s drawings, even more than those of, say, Leonardo, are palimpsests on which one may find jostling each other sketches and studies for various projects side by side with drafts of poems, stray remarks or quotations that seem to have drifted through his mind, lists of expenses and other items that are apparently not by Michelangelo at all. His correction of another apprentice’s attempt to copy those

Gayford, Martin. Michelangelo: His Epic Life (Kindle Locations 1045-1054). Penguin Books Ltd. Kindle Edition.