Fig. 2From: A high sensitivity, low noise and high spatial resolution multi-band infrared reflectography camera for the study of paintings and works on paper a The wavelength dependence for the difference in reflectance (i.e. contrast) for light which is transmitted through a paint layer and then is reflected off a white ground versus light which is reflected off lampblack. b The reflectance of lampblack, a common underdrawing material, and chalk, an ideal whiteBack to article page