pbm

The PBM format is read and written by the pbm* tools in the Netpbm package.

PBM (Portable Bitmap) is the simplest of the Netpbm formats, storing 1-bit (black-and-white) raster images. It comes in two variants: a plain ASCII form (magic number P1) and a binary form (magic number P4). The header records the format, width, and height; pixel data follows, with 0 representing white and 1 representing black.PBM is a lossless format intended as a least-common-denominator for image processing pipelines: nearly every Netpbm utility can read and write it, making it useful as an intermediate format when chaining conversion tools.

Stores only black and white (1 bit per pixel); for grayscale use PGM and for color use PPM. The binary form is more compact but the ASCII form is human-readable. Files have no compression, so they can be much larger than equivalent PNGs.

PBM originated in Jef Poskanzer's PBMplus toolkit in 1988 and is now maintained as part of the Netpbm project.

pgm(5), ppm(5), pnm(5), netpbm(1), pnmtopng(1)