Netpbm formats

File Format
Name	Netpbm formats
Ontology	Electronic File Formats Graphics Netpbm formats
Extension(s)	.pbm .pgm .ppm .pnm .pam
PRONOM	fmt/408, fmt/405, others

Overview

The Netpbm formats are a set of uncompressed raster image file formats, associated with the Netpbm library and suite of image processing utilities.

PBM (portable bitmap) is a bi-level image format.

PGM (portable graymap) is a grayscale image format.

PPM (portable pixmap) is a color image format.

PNM (portable anymap) is a collective name for PBM, PGM, and PPM. A .pnm file may use any of those formats.

PAM (portable arbitrary map) is a more sophisticated format which supports everything the PBM, PGM, and PPM formats do, and then some. Some resources name this format "Portable Any Map", but that appears to be an error.

Identification

Each file begins with two ASCII characters, which serve as a signature.

The PBM, PGM, and PPM formats come in two varieties: a text ("plain") format, and a binary ("raw") format. PAM is binary-only.

Format	Signature	PRONOM
PBM, text	P1	x-fmt/164
PGM, text	P2	fmt/407
PPM, text	P3	x-fmt/178
PBM, binary	P4	fmt/409
PGM, binary	P5	fmt/406
PPM, binary	P6	fmt/408
PAM	P7	fmt/405

See also

• PFM

Specifications

• PBM Format Specification
• PGM Format Specification
• PPM Format Specification
• PAM Format Specification

Software

• Netpbm

External links

• Wikipedia: Netpbm format
• Wikipedia: PAM graphics format