HDR, High Dynamic Range Image File (.hdr)
The HDR Raster image file format
Files that Have the HDR extension are raster image files saved in a the High Dynamic Range format. This format is most commonly used for digital photos. Images saved as HDR images are used for enhancing images and photos with regard to color and brightness. Washed out areas, shadows and other dynamics can be easily fixed in HDR images.
Technical details of HDR files
The pixel values of a HDR file can cover the whole tonal spectrum that is present in the real world. HDR images are able to display the largest possible range of pixel values. Thus, direct light and sunshine as well as extreme shadows can be captured with a life-like portrayal of colors. HDR images can be created either by merging different photographs in a specific way, by using special image sensors, or via computer rendering.