"Del modo di colorire in tela" : étude et conservation-restauration de deux fragments de peinture sur toile italienne de la fin du XVe siècle ou du début du XVIe siècle (Paris, musée Jacquemart-André) : étude d'une méthode d'amincissement du vernis au mo…

The subjects of this Conservation Thesis are two italian paintings attributed to Agnolo and Bartolomeo degli Erri (active in Modena, 2nd half of the XVth c.), from the Jacquemart-André Museum (Paris). The two scenes, figuring Saint John the Baptist and a young saint and Saint Benedict and saint Elizabeth, are painted on canvas glued on to a wooden panel.
Prior to the conservation treatment, a thorough examination of the paintings was made, concerning their conservation state as well as the execution techniques. The support of these works presented conservation problems (the adherence between canvas and wood was lost in several places, several canvas's lumps), a few loose painted areas, and a very oxydized yellow varnish.
The scientific examination (UV, IR, X-Ray microfluorescence, cross sections...) revealed the stratigraphy of the painting, including a twofold preparation: very thin gesso layer (calcium sulfate), and a white imprimitura probably in an oil medium. The two scenes showed to be two fragments of one unified composition, featuring a golden background, as well as a tree between the two male saints, hidden by an azurite overpaint. The central part of the scene is now missing.
The two fragments appeared to be very overpainted, following several restoration campaigns, hiding the original unified state of the composition. With these technical data, a historical research was conducted, proposing to re-attribute the two fragments to a Lombard artist, very close to the Milanese painter Bramantino between the end of the XVth c. and the beginning of the XVIth c.
Since a cleaning was to be undertaken, the scientific research deals with cleaning topics: a procedure for a solubility test providing an adapted solvent selection, and the study of a wax emulsion used for a thinning of the varnish.
The conservation treatment implied conservative measures (anti-insects treatment by anoxia, fixing of the loose painted layers) and a cleaning treatrnent, willingly very slow and progressive in order to respect the integrity of the painting. Given the-time-consuming character of the procedure, further treatment including retouching and varnishing will be applied to only one of the two fragments (the Saint John the Baptist and a young saint).