The format is designed for Kodak cameras to store uncompressed RAW images in their original form without auto color and white balance correction. The file has a TIFF-structure that allows you to edit the color temperature and exposure of the finished image without losing information and quality, which is something that cannot be done with JPEG format images.
This is a graphic file format that supports HDR. It is used for exchanging graphics data between applications. It is also used for development in the Netpbm suite of graphics editors. A PBM image has either a per-pixel RGB structure or instructions for representing grayscale tones.