A relationship between the watercolour additions and those in pen and ink in a group of drawings from the Jabach Collection (1618—1695), now in the Département des Arts Graphiques at the Louvre, Paris, is presented here for the first time. The drawings discussed in this study were done by Giovanni Antonio Boltraffio, Andrea Solario and Bernardino Luini, as well as by Nicolas Poussin, with additions and integrations executed by Charles Errand on the occasion of the publication of Leonardo's Trattato della Pittura (Paris, 1651). Among the artists Everhard Jabach employed for the "improvements" on the drawings in his collection before selling them to the King of France in 1671, was Michel Corneille the Younger (1642—1708) to whom Jabach assigned a particular role, as has been demonstrated in previous important studies by Catherine Monbeig Goguel.

The present article considers a broader cultural context including mid-seventeenth century Rome, Giovan Pietro Bellori and the veneration for Raphael, to whom at least two of the drawings in the Jabach Collection here examined (now assigned to Solario) were attributed at the time. Certain drawings executed at Jabach's time by French artists, such as Charles Errard, Noël Coypel and Michel Corneille the Younger (hitherto unpublished), seem to show familiarity with the Raphael—Solario drawings, now in the Louvre, retouched and integrated at that time with landscapes and vegetation.