Gimp: Save tiff with a “Group 4 Fax” compression

Question

I'm using Gimp and I need to save a tiff file with a "Group 4 Fax" compression. I've followed the instructions to have that option enabled on the "Save as Tiff" dialog (see bottom of the linked page), but the option still appears grayed out...

Any idea what I may be doing wrong?

Answer 1

Group 4 Fax compression only applies to bitmap (1 bit per pixel) images. Change the image to bitmap, then the option should be available.