Posted: 2006-06-02T10:03:16-07:00
You may need to upgrade. We tried your command with ImageMagick 6.2.7-8, the current release, and it worked fine (produced a usable Group4 TIFF image).
Use https://github.com/ImageMagick/ImageMagick/discussions instead.
https://imagemagick.com/discourse-server/
https://imagemagick.com/discourse-server/viewtopic.php?t=6689