SCIENTIFIC EXAMINATION OF THE MANTEGNA'S PAINTINGS IN SANT'ANDREA, MANTUA: THE FAMILIES OF CHRIST AND ST.JOHN THE BAPTIST AND THE BAPTISM OF CHRIST

Mantegna was a supremely confident draughtsman and there is no evidence in his underdrawings of the use of any aids for the reproductions of cartoons or the enlargements of studies on paper. Instead, he seems to have drawn directly on the gesso making his first marks with a brush and very diluted carbon black ink, perhaps guided by a smaller scale sketch on paper. Once the placement of the main features was settled, Mantegna developed the underdrawing using a darker more pigmented liquid material still applied with a brush and contours were defined with broad, thick and fluent lines which have been also painted at sight. The modelling of forms has been achieved at the level of painted surfaces which seems to be a further indication of Mantegna’s late painting production. All these features seem to be present in both paintings and particularly on the central part of the Family of Christ and Saint John Baptist. The underdrawings of the figures of Saint Joseph and Zacharias appear to be less fine and accurate then those observed on the central part of the painting. The very bad state of conservation of these pictorial layers do not allow a clear assignment to Mantegna and the contribution from another artist (his son Francesco?) can only be hypothesized. Given the fact that the Baptism of Christ undertook severe restoration interventions and suffered in the past from the exposure to unsuitable environmental conditions, it is hard to draw conclusive results from both the historical documentation and multi spectral imaging examinations. Analogies with the underdrawings documented in the central part of the Holy Family of Christ and St John Baptist exist, but their poorer definition do not allow a certain attribution to the typical late painting technique of Andrea Mantegna and, it is well understandable why such a controversial attribution went through many centuries. The analytical results seem to confirm that both canvas paintings have been prepared in the usual way with a gypsum preparatory ground; the contemporary presence of elements such as Fe, Si, Mn and Al can be associated with the use of umber mixed with red ochre pigments added to the ground to achieve a warmer tonality of the upper paint layers. As far as the pigments’ composition is concerned the analyses confirmed for both paintings the use of almost the same paint palette and highlighted the constant presence of smalt which has been identified for the first time on Mantegna paintings. This result, that in principle would suggest a common authorship for the two paintings, would also need to be further confirmed through other analyses capable to characterize the polychrome structure, as the profound understanding of the way in which paint layers and pigments have been applied in terms of thickness and morphology can be sometime conclusive in conducting technical study of paintings.