The Guadalupe Tilma, Miracles
Standing
Concerns Investigation Verdict
Currently States Philip Callahan's 1979 infrared study reported no underdrawing, sizing or varnish across the image's original figure, while identifying the moon, gold rays and angel as later painted additions.
Philip S. Callahan's The Tilma Under Infra-Red Radiation (Center for Applied Research in the Apostolate, CARA Studies on Popular Devotion, vol. II, Guadalupan Studies no. 3, 1981) is a technical infrared imaging study of the Guadalupe tilma. The method is infrared reflectography, a standard art-conservation technique that can reveal an underdrawing, the preparatory sketch an artist makes before painting, if one is present beneath the visible paint layer. Callahan's imaging found no underdrawing on the tilma's image. Proponents of the image's traditional origin cite the absence as evidence against ordinary painted production, since a conventional painting is normally expected to show one. Conservators and Callahan's own study both note the caveat that infrared analysis cannot rule out lost, unconventional or since-degraded techniques that would leave no underdrawing detectable, so the absence establishes only that none survives to be found, not by itself how or when the image was produced.
Source The Tilma Under Infra-Red Radiation, Philip S. Callahan