This small Psalter leaf illustrates the fact that, although skilled scribes were available in many monasteries in the XIIIth century, some of the monks who attempted to apply and burnish the gold leaf were still struggling with many problems of illumination. The famous treatise De Arte Illuminandi and Cennino Cennini's Trattado were both of later date. These works gave directions on how to prepare and use the glair of egg, Armenian bole, stag-horn glue, and hare's foot, and on how to burnish the gold with a suitable wolf's tooth. These books might not have been too helpful, however, for the author of the De Arte Illuminandi adds, 'Since experience is worth more in all this than written documents, I am not taking any special pains to explain what I mean.'
