Plaster casts are image vehicles par excellence. They can reproduce and multiply three-dimensional form, and serve the dissemination of visual ideas from one place to another; they can record lost stages of a work’s appearance, e.g. pre-completion, pre-damage, pre-destruction or pre-restauration. Often perceived as perfect one to one copies of the external form of a three-dimensional work, they can also accidentally or deliberately differ from what they reproduce, and with their white and even surface they can condition the perception of the works they represent. Thus, cast are also works in their own right, objects with their own history. Yet, for long, they proved rather evasive. Until recently, there have been few attempts to date them either through material or technical analysis. Given their status as copies, historicaly they were often not documented, and where archival references to casts exist, the objects under discussion are often either lost or impossible to identify beyond reasonable doubt. This situation is changing, as a recent exhibition at the Villa Medici in Rome (November 2019-March 2020) demonstrated