Just in case you’re unfamiliar with the therm, HDRI stands for High Dynamic Range Imaging. As I’ve discussed before, a regular photo can’t capture the full range of lights and shadows that the human eye can see. Photographers have long learned to avoid high-contrast situations or to use them to create artistic effects. It all changed when Paul Devebec presented at SIGGRAPH 1997 a method for combining several images with different exposures into one single image with a much higher range of luminosity. To put things in perspective, a camera sensor can cope with contrast ranges on the order of 4000:1, while a scene of a room with an outside view in full sun (something our eyes see every day) has a dynamic range of 100,000:1.