No. 1. Michael Attas et al., spectroscopic image analysis of Veit Hirschvogel, the Elder, Untitled (The Holy Trinity), ink, wash, charcoal, red pigment on paper, 39.9 × 39.1 cm, 15th century. (a, top) Drawing as it appears to the eye. (b, bottom) Drawing enhanced using spectroscopic imaging and principal-components analysis to highlight differences among near-infrared spectra of materials. Charcoal lines are coded red. (Collection of the Winnipeg Art Gallery; Acquired with the S.C. Eckhardt-Gramatté Memorial Fund, [Accession # G-75-3].).
© E. Michael Attas. Photo © Cathy Collins, The Winnipeg Art Gallery