This format is used to compress TIFF images when sending them via fax machines. This format helps reduce the data transmission time. Group 3 eliminates redundant data during compression in order to reduce file size. The standard 10:1 compression ratio may be increased to the user's preferences, but it can lead to a significant loss of image quality.
was developed for the first mass-produced e-book reader – Rocket eBook. The format is written in Ruby. RB files are containers holding the entire content for a Rocket eBook device. It has DRM protection capability which is not used in the books published at present due to the format’s lack of popularity.