Fig. 5From: Materials and techniques used for the “Vienna Moamin”: multianalytical investigation of a book about hunting with falcons from the thirteenth centuryComparison of the reflectance spectrum obtained from a green area (red) with a reference spectrum of gypsum measured in transmission (blue). The strong SO4 vibrations (ν3 and ν4) are inverted, but the OH bands are almost invisibleBack to article page