PPM (Portable pixmap format)

A PPM file is a Portable Pixel Map file, which is an image file format used to store images in a simple binary format. Red, green, and blue pixel data is stored in an uncompressed form, making it easy to process.

The format comprises three bytes for each pixel, one for the red component, one for the green component, and one for the blue component. Hence it is a 'true colour' image, using the full 24 bit representation. Each of the single colour planes is actually grey scale image, hence a PPM file can be separated into three PGM files, or generated from three PGM files.