Netpbm formats

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

Contents

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

Specifications

Software

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