In-studio tracing proves that Nelli's serial Saint Catherines were all drawn from the same cartoon. Amongst the revelations of Nelli's exhibit at the Uffizi Galleries in 2017 is the serial nature of her production. Nelli was helped by the other nuns in the convent whom she trained in the art of painting. Five images of Saint Catherine (be she of Siena or de’ Ricci is voluntarily ambiguous) show the use of the same cartoon outline as the basis of the small devotional painting. The San Salvi image is considered Nelli's original. In Plautilla Nelli, Art and Devotion in Savonarola’s Footsteps (Ed. Fausta Navarro, Sillabe. 2017), Rossella Lari discusses the art of copying: "In the case of the replicas of Saint Catherine of Siena/de’ Ricci, the use of the same cartoon or some of its derivations must have become necessary to allow more nun artists to produce paintings and in that way satisfy the multitude of requests from lay people for private devotional works of art. Such demand must have been huge, if truly, as Vasari reports, “in the houses of gentlemen throughout Florence, there are so many pictures, that it would be tedious to attempt to speak of them all,” and in fact, it was this flourishing business that made it possible for the convent to survive."