Did Caravaggio employ optical projections? An image analysis of the parity in the artist's paintings

摘要

We examine one class of evidence put forth in support of the recent claim that the Italian Baroque master Caravaggio secretly employed optical projectors as a direct drawing aid. Specifically, we test the claims that there is an "abnormal number" of left-handed figures in his works and, more specifically, that "During the Del Monte period he had too many left-handed models." We also test whether there was a reversal in the handedness of specific models in different paintings. Such evidence would be consistent with the claim that Caravaggio switched between using a convex-lens projector to using a concave-mirror projector and would support, but not prove, the claim that Caravaggio used optical projections. We estimate the parity (+ or -) of each of Caravaggio's 76 appropriate oil paintings based on the handedness of figures, the orientation of asymmetric objects, placement of scabbards, depicted text, and so on, and search for statistically significant changes in handedness in figures. We also track the direction of the illumination over time in the artist's oeuvre. We discuss some historical evidence as it relates to the question of his possible use of optics. We find the proportion of left-handed figures lower than that in the general population (not higher), and no significant change in estimated handedness even of individual models. Optical proponents have argued that Bacchus (1597) portrays a left-handed figure, but we give visual and cultural evidence showing that this figure is instead right-handed, thereby rebutting this claim that the painting was executed using optical projections. Moreover, scholars recently re-discovered the image of the artist with easel and canvas reflected in the carafe of wine at the front left in the tableau in Bacchus, showing that this painting was almost surely executed using traditional (non-optical) easel methods. We conclude that there is 1) no statistically significant abnormally high number of left-handed figures in Caravaggio's oeuvre, including during any limited working period, 2) no statistically significant change in handedness among all figures or even individual figures that might be consistent with a change in optical projector, and 3) the visual and cultural evidence in Bacchus shows the figure was right-handed and that the artist executed this work by traditional (non-optical) easel methods. We conclude that the general parity and handedness evidence does not support the claim that Caravaggio employed optical projections.