Netpbm formats

File Format
Name	Netpbm formats
Ontology	Electronic File Formats Graphics Netpbm formats
Extension(s)	.pbm, .pgm, .ppm, .pnm
MIME Type(s)	image/x-portable-anymap, others
PRONOM	fmt/408, others
Released	1988

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

Formats

• 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: Refer to PAM (Portable Arbitrary Map). Although PAM is one of the Netpbm formats, it's different enough that it's best documented in a separate article.

Identifiers and 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 (or "plain" or "ASCII") format, and a binary (or "raw") format.

Format	Signature	PRONOM	MIME type
PBM, text	P1	x-fmt/164	image/x-portable-bitmap, image/x-portable-anymap
PBM, binary	P4	fmt/409
PGM, text	P2	fmt/407	image/x-portable-graymap, image/x-portable-anymap
PGM, binary	P5	fmt/406
PPM, text	P3	x-fmt/178	image/x-portable-pixmap, image/x-portable-anymap
PPM, binary	P6	fmt/408

See also

• PAM (Portable Arbitrary Map)
• PFM (Portable Float Map)

Specifications

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

Software

The PBM/PGM/PPM/PNM formats are widely supported. Software listed here has been arbitrarily selected.

• Netpbm
• ImageMagick

Sample files

• http://www.fileformat.info/format/pbm/sample/index.htm
• http://samples.libav.org/image-samples/ → *.ppm, *.pgm
• http://www.csbruce.com/cbm/ftp/images/pbm/

Links

• Wikipedia: Netpbm format
• PBM, PGM, PNM, and PPM File Format Summary, from the Encyclopedia of Graphics File Formats
• Graphic describing PGM format