TIFF Group 4 is a protocol used for sending fax documents through an ISDN line. In this group scan lines are encoded with reference to the previous one, creating better compression ratios.
TIFF Group 4 2D - encoding is more than Group 3 encoding. Each scan line is compared to the scan line before it. High levels of compression can be used based on vertical attributes of the image.
TIFF Group 4 support is included in the following Black Ice printer drivers: