group 3 format TIFF

[fikri@werty.wasantara.net.id]

If I check the tiff file I got the message below :

FaxServer:/usr/local/sbin# tiffcheck /home/fikri/poster1.tif
REFORMAT+RESIZE+REIMAGE
Document is not a bilevel image (bits/sample 8).
Document requires reformatting, not in Group 3 format.
Document requires resizing to adjust page width (convert to 1728, document is 27
4).

what can I do to make the file TIFF in "Group 3 format"  ? 



-fikri-