Netpbm formats

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== See also ==
== See also ==
* [[ImgStar]]
* [[ImgStar]]
* [[MTV ray tracer bitmap]]
* [[Netpbm]]
* [[Netpbm]]
* [[PAM (Portable Arbitrary Map)]]
* [[PAM (Portable Arbitrary Map)]]

Revision as of 01:47, 16 January 2015

File Format
Name 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.

The Netpbm formats are often used as "neutral" or "universal" image formats. It's not unusual for an image format's reference software to include a utility to convert to and from one of the Netpbm formats (and perhaps no other formats). Many of these conversion utilities have ultimately been incorporated into the Netpbm software.



  • 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

Multi-image files

Although the Netpbm formats are usually thought of as single-image formats, the binary formats technically do support multiple images per file. This is accomplished simply by concatenating single-image files together. Such multi-image files are probably not well-supported.

See also



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

Sample files


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