Infrared (IR) reflectance photography of the painting <i>Tannhäuser</i> revealed changes made by the artist. Design variations between the IR photograph and the painting itself show that the composition was reworked, partially because of complaints about the nudity of some of the figures. A photograph of the first state of the painting was taken by Mme. Fantin-Latour in 1886. The background was also changed. Writing to a fellow artist in 1888, Fantin discussed his method of doing a complete shaded drawing in charcoal on the canvas, and only then deciding whether to add color with pastel or oil paint. Examination of this painting under the microscope confirmed this technique; charcoal particles are visible underneath the translucent paint layers.