PBM
Portable Bitmap
PBM is a simple monochrome image file format designed to store binary black-and-white graphics.
What is Portable Bitmap?
The Portable Bitmap (.pbm) format is part of the Netpbm project, a family of image formats created to easily exchange bitmap images across different platforms. PBM files store image pixels as a grid of 1s and 0s, where 1 represents black and 0 represents white (or vice versa in plain text variants). Because of its human-readable plain text variant (P1) and simple binary variant (P4), the format is frequently used in computer vision, OCR preprocessing, and simple fax transmissions.
Advantages
- Extremely simple structure makes it easy to parse with custom scripts
- Human-readable plain text variant (P1) for debugging
- Lossless storage of binary pixel data
- Supported by many image processing and scientific libraries
Limitations
- Supports strictly monochrome (1-bit black and white) images
- Lack of advanced compression results in large file sizes for complex graphics
- Not suitable for standard web publishing or modern photography
How to open Portable Bitmap files
GIMP
IrfanView
XnView
ImageMagick
Netpbm tools
Common use cases
- Storing binary masks in computer vision algorithms
- Preprocessing images for Optical Character Recognition (OCR)
- Simple fax and document scanning pipelines
- Educational purposes in computer science for teaching image encoding
Convert PBM files
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Frequently asked questions
A PBM file is a monochrome (black and white) image format that stores pixel data as a grid of binary values (0s and 1s).
You can open PBM files using image editors and viewers like GIMP, IrfanView, XnView, or command-line tools like ImageMagick.
No, PBM strictly supports 1-bit black and white images. For grayscale, the PGM format is used, and for color, the PPM format.
PBM files use minimal or no compression, meaning every pixel is explicitly stored, which can result in large file sizes for high-resolution images.