is an e-book format developed for the Psion Series 3 platform used in the 1990s. It contains text and its formatting parameters. This e-book format was used exclusively in Psion devices.
The G3 format is used to compress image files in TIFF format when sending faxes. The compression algorithm allows for the use of a standard 10-times compression, which can be increased. It is used to remove excess image data, which makes it possible to reduce the size of the image and speed up delivery.