This is a format for compact font storage in the OpenType system, allowing for the rasterization of text information. It differs from TrueType in its abilities to describe font symbols and with its font structure variation algorithm, depending on the change in size. CFF allows for increased screen clarity with high resolution, but this is not due to the font, but its rasterization.
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.