Ciao Ivana, se cerchi specificamente "preparatory cartoons" vedrai che tutti i musei piu' importanti (sotto hai il link al Louvre, per es.) utilizzano quella definizione.
Buon lavoro.

Fresco Cartoon - full scale drawing of the future fresco. Cartoons are drawn on regular paper with pencil, graphite, charcoal, sepia chalk, etc., etc. The purpose of a cartoon is a thorough study and final rendition of the composition, light, shadow, details of the future fresco, it is a preparatory drawing taken to the next level. Correctly done cartoon is a "stand along" artwork. Although optional in other painting mediums, Cartoon is essential when paintng in Fresco not only as the main guideline for transferring the design onto freshly laid (fresco) plaster, but also as the main tool and method of understanding and orcestrating the steps for painting of the corresponding fresco.

http://www.fresco-techniques.com/fresco-definition.html

Giulio ROMANO (model), Francesco PENNI (preparatory cartoon), François BONNEMER (Gobelins cartoon)
http://www.louvre.fr/llv/oeuvres/detail_notice.jsp?CONTENT<>...

http://en.wikipedia.org/wiki/Cartoon

http://www.thatsart.it/pdf/200207.pdf