Michelangelo, The Torment of Saint Anthony

Michelangelo's The Torment of Saint Anthony, painted circa 1487–88 Photograph: Kimbell Art Museum, Fort Worth

An infrared reflectogram of the same picture, which shows the two types of underdrawing Michelangelo used prior to painting. A brush in a liquid medium for the outlines of the figures and draperies, and a combination of parallel- and cross-hatching for the landscape and rocky outcrop Photograph: Paintings Conservation Department, The Metropolitan Museum of Art, New York

An x-ray of the painting, revealing the grain of the poplar panel beneath. The wood is in excellent condition, despite a few small wormholes. Michelangelo covered the panel with primer first, then partially scraped it away to create the dark shapes of Saint Anthony and some of the demons Photograph: Paintings Conservation Department, The Metropolitan Museum of Art, New York

This detail shows the spiny fish-demon holding a firebrand. Michelangelo elaborated on Martin Schongauer's engraving by adding fish scales Photograph: Kimbell Art Museum, Fort Worth

This infrared reflectogram shows the brush underdrawing that establishes the forms, including a shift in the position of the firebrand Photograph: Kimbell Art Museum, Fort Worth

Michelangelo's short, parallel incisions in the demon's teeth are just about visible in this detail Photograph: Kimbell Art Museum, Fort Worth

The fish-demon's tail has been moved to encircle the head of the smaller demon Photograph: Kimbell Art Museum, Fort Worth

Michelangelo's delicate parallel-hatching is faintly visible in the face of Saint Anthony. There is also a correction to the upper contour of the bat-like demon's arm, where the artist applied a stroke of light paint (lower right) Photograph: Kimbell Art Museum, Fort Worth

Michelangelo painted the scales of the spiny fish-demon after visiting the local fish market. This detail reveals how he scraped away the background paint to reveal the primer beneath, helping to create the curve of the fish Photograph: Kimbell Art Museum, Fort Worth