ilbmtoppm

Convert an ILBM file to a PPM image

$ ilbmtoppm [path/to/file.ilbm] > [path/to/file.ppm]

$ ilbmtoppm [[-t|-transparent]] [color] [path/to/file.ilbm] > [path/to/file.ppm]

$ ilbmtoppm [[-ig|-ignore]] [chunkID] [path/to/file.ilbm] > [path/to/file.ppm]

$ ilbmtoppm [[-m|-maskfile]] [path/to/maskfile.pbm] [path/to/file.ilbm] > [path/to/file.ppm]

ilbmtoppm [-verbose] [ilbmfile]

-verbose
    Print progress messages (image count, modes) to stderr

ilbmtoppm is a utility from the Netpbm graphics toolkit that converts ILBM (InterLeaved BitMap) files—originally from Amiga computers—into PPM (Portable Pixmap) images. ILBM is an IFF-based format supporting planar pixel storage, multiple bit depths, and special modes like HAM (Hold-And-Modify, up to 4096 colors on 12-bit hardware), HAM6, and EHB (Extra Half-Brite, 64 colors with halftone effects).

The command reads an ILBM file (or stdin if unspecified) and outputs PPM to stdout. It handles multi-image files by producing one PPM per image, decompresses packbits compression, and preserves cycle modes, transparency, and LUTs where supported. This enables seamless integration with other Netpbm tools for processing legacy Amiga artwork, animations, or demos.

Common use cases include batch conversion of Amiga disks, preparing graphics for modern editors, or archiving. Limitations apply to rare ILBM extensions, but core features cover most files from 1985-1990s software like Deluxe Paint.

Supports common ILBM variants only; rare modes/extensions may fail. Always outputs to stdout (redirect for files). Multi-image files produce sequential PPMs without separation.

Omit ilbmfile or use - for stdin. Output always PPM to stdout: ilbmtoppm foo.ilbm > foo.ppm.

Expands HAM to full RGB; EHB simulates halftones accurately in PPM.

Added to Netpbm in early 1990s by pioneers like Jef Poskanzer; evolved with Amiga emulation boom for converting IFF/ILBM from floppy archives.

showilbm(1), lstilbm(1), ppm(5)