Unfortunately the GIMP doesn't support writing out 1 bit TIFF images. My own solution is to use Save As, choose uncompressed or some other compression scheme that supports grayscale TIFF images, then use another application to convert back to 1 bit and apply the G4 compression. Ugly? You bet. Unfortunately, there doesn't seem to be a lot of interest among most of the GIMP developers for supporting single bit depth images. Most of them are more interested in typical "graphics art" type images that require at least 8 bits per pixel. One of these days, some of us who need to work with one bit images are going to have to bite the bullet and jump in with both feet to contribute to the development effort and address this restriction.

s/KAM

I am trying to edit g4 compressed tiffs, and have run into some difficulty. When I open a tiff Gimp alerts "unknown field with tag 32934 (0x80a6) encountered." However, the tiff does open. After editing I attempt to save back to the tiff. The following errors are displayed; "Failed a scanline write on row 0", and "Bits/sample must be 1 for group 3/4 encoding/decoding." I have tried to decompress using libtiff tools first, then edit and save back as an uncompressed tiff, finally converting to g4 using libtiff tools, but encounter the same errors in tiffcp. I'm hoping there is a setting in Gimp that will allow me to edit g4 and save as g4 without libtiff tools or errors. Is there?