Leonardo: Discoveries from Verrocchio's Studio considers two notoriously knotty questions: what was Andrea del Verrocchio's production as a painter, and what lessons did his star pupil Leonardo da Vinci learn (if any) as a painter from his teacher? The book opens with an excellent overview of the issues by Kanter. As he points out, documents make evident that Verrocchio must have been a painter of some renown. Among the most important of these documents is one from 1485, recording how Verrocchio had been commissioned to paint the Madonna di Piazza altarpiece (also known as the Pistoia altarpiece; chapel of the Sacrament, Cathedral of San Zeno, Pistoia), which was complete, or nearly so, before that date. Verrocchio's production as a painter is also apparent from writings of contemporary chroniclers who celebrate him as a painter (as well as a sculptor). Despite this, scholars have long debated the extent to which Verrocchio was a painter and when he began painting; indeed, some even question whether he was ever a painter at all. Vasari sowed the seeds of doubt in his famous account of Verrocchio giving up painting when he saw the angel painted by his pupil, Leonardo, in the Baptism of Christ (1460s and 1470s, Galleria degli Uffizi, Florence). The situation is compounded by the fact that we do not have a single painting definitively by Verrocchio and because most paintings associated with his bottega were made collaboratively, even small-scale paintings.

Kanter offers a refreshing and often convincing set of arguments concerning the attribution of paintings to Verrocchio and Leonardo. As he rightly points out, there is no good reason to suppose we will find Verrocchio's hand in paintings with the same level of quality as his sculptures, or that his paintings display the same set of interests evident in his sculptures. These are proposals that must be proven, not assumed. Kanter also usefully challenges the problematic tendency to attribute paintings deemed of a higher quality to Leonardo and those deemed deficient to Lorenzo di Credi, a painter known to have worked in Verrocchio's bottega. As Kanter notes, this system often collapses when one compares works from Credi's known output to possible attributions. Instead, Kanter searches for “unconscious habits of mind” of each artist, evident across a number of paintings. This leads him to make some intriguing suggestions for early paintings by Leonardo. If correct, Kanter's picture of Leonardo's early production is one far removed from the artist's later paintings in terms of technique (he proposes Leonardo worked first in tempera) and approach. Kanter's early Leonardo is far from the artist who later demonstrates such a profound interest in vivacity, expressed through every aspect of his painting, including composition and sfumato.

The book concludes with technical reports by Mottin and Albertson about two small paintings associated with Verrocchio's workshop—the Annunciation (Musée du Louvre) and A Miracle of Saint Donatus of Arezzo (Worcester Art Museum). These paintings formed part of the predella for the Madonna di Piazza altarpiece, and their attribution has long been debated. Most designate them “workshop of Verrocchio,” but some attribute them to Credi, and a few attribute one or both to Leonardo. No definitive conclusion is reached here and in fact, there is disagreement among the contributors. But the technical reports provide much valuable information about how the paintings were made. Mottin and Albertson suggest the design and painting stages were carried out by more than one artist. Infrared reflectography reveals different tools were used for the underdrawings. Furthermore, Albertson notes two styles in the Worcester panel's underdrawings, suggesting different hands. The reports also conclude that although designs for both panels were carefully planned, changes were made during the painting stage. Moreover, diverse techniques and paint handling suggests both works were made by two or more artists. Although some of the Worcester panel suggests affinities with tempera painting, the technical study establishes it was painted in oil. Mottin asserts that the Annunciation was painted in oil (not tempera as is sometimes claimed), though the painting was not sampled to confirm this. Albertson makes the fascinating observation that some of the painting in the Worcester panel adopts a tempera-like approach, despite being executed in oil. This points to an experimental approach to technique typical of objects across media produced in Verrocchio's workshop.