Examination of paintings by infrared radiation often reveals changes in composition, damages, fillings and retouches. Its most frequent use is in the detection of underdrawing executed with carbon pigments. Thin paint layers, opaque to visible light, are often partially transparent to radiation in the 700 nm to 2,000 nm range. White gesso, and to a lesser extent other light-coloured grounds, reflect infrared rays, but where there is drawing reflectance is reduced. This phenomenon can show the carbon-based under-drawing beneath paint layers. This can be extremely informative about the history and construction of the painting. We have equipment that will capture infrared in the region of 1,000-1,300nm & 1,700-2,000nm. We are currently developing a new infrared mosaicing system and the website will be updated with this information.