pbmtog3 man page

pbmtog3 — convert a PBM image into a Group 3 MH fax file


pbmtog3 [-reversebits] [-nofixedwidth] [pbmfile]


pbmtog3 reads a PBM image as input and produces a Group 3 MH fax file as output.

You can also generate a TIFF file that uses the same encoding inside, with pamtotiff.

There is no program in Netpbm that generates other fax formats, such as MR and MMR, but pamtotiff can generate TIFF files that use those encodings.


This option causes the output to have the bits in every byte reversed so the least significant bit becomes the most significant bit. Apparently, there is some ambiguity in transmission protocols so that the bits get reversed on transmission, and this compensates for that. If you get a whole bunch of "bad code word" messages when you try to read the G3 file (e.g. with g3topbm), try using this option. Note that the output is not G3 when you use this option.
Most fax machines expect the image to be 1728 columns wide, so pbmtog3 cuts the output to this width by default. If you want to keep the width of the original image, use this option.

This option was new in Netpbm 10.6 (July 2002). Before that, pbmtog3 always kept the width of the original image.

See Also

g3topbm(1) , pamtotiff(1) , pbm(1)



Copyright (C) 1989 by Paul Haeberli <paul@manray.sgi.com>.

Document Source

This manual page was generated by the Netpbm tool 'makeman' from HTML source. The master documentation is at


Referenced By

g3topbm(1), pbmtopsg3(1).

Explore man page connections for pbmtog3(1).

netpbm documentation 03 December 2008