A photographic analysis method that captures the natural or reflected emission characteristics of infrared radiation. First available in the 1930s, the technique was further developed during WWII for aerial reconnaissance. Infrared photography uses a specially designed film sensitive to infrared radiatuion or a dedicated electronic camera for image capturing. When an object or painting is illuminated with natural or incandescent light, infrared radiation can intereact with not only the surface but also underlying layers. Since the absorption of infrared wavelengths varies for different pigments, the resultant image can help distinguish the pigments that have been used in the painting or underdrawing.
See also false-color infrared film.