Radiance (HDR) is a 32‑bits-per-channel file format used for high dynamic range images. This format was originally developed for the Radiance system, a professional tool for visualizing lighting in virtual environments. The file format stores the quantity of light per pixel instead of just the colors to be displayed on-screen. The levels of luminosity accommodated by the Radiance format are far higher than the 256 levels in 8‑bits-per-channel image file formats. Radiance (HDR) files are often used in 3D modeling.