I've been reading David Talbot Rice's "The Appreciation of Byzantine Art", a 1972 contribution to a series of books from Oxford University Press on the appreciation of various types or periods of art. He referred in passing to the Wolfenbuttel Muster Buch (pattern book), a 13th century book of pattern drawings depicting figures from various Byzantine icon compositions. Drawn on parchment(?) and bound together into a folio, art historians believe the artist was a Venetian working around 1260. Parchment being quite costly (papermaking, although known in Spain, was just beginning in Italy and France), and it appears that the drawings are rendered over letterforms (or was repurposed and written over.)
They are quite well done, drawn presumably with a brush. Thin washes of diluted ink(?) were used to lightly model the forms and the shadows. There is much that can be learned studying these drawings, especially the drapery, which is si beautifully rendered. These figures are from the icon of the Anastasis ("Descent Into Hell"), including, it appears, the Prophet Isaiah, Abel the Just and Moses.
Despite the title, I can only guess at the size of each page!
Below are some additional plates from the patternbook, the first two related to the Anastasis icon, the last, figures of the evangelists.