Zetafax fax file
File type: Graphics file
A .g3f file is a Zetafax fax file containing a fax image encoded in a high-resolution TIFF-based format for Group 3 fax transmission.
It belongs to Zetafax, fax communication software for Microsoft Windows.
File type category:
Graphics file
Date updated: October 9, 2026
Zetafax was developed by Equisys for sending, receiving and managing faxes on Microsoft Windows. A .g3f file stores fax-page image data used by the software.
The format is associated with high-resolution TIFF-based fax imagery and Group 3 fax compression. TIFF (Tagged Image File Format) is a widely supported tagged bitmap-image format used on both PCs and Macintosh computers. TIFF images can be stored at any resolution in black and white, grayscale or color, using uncompressed or compressed representations such as LZW, Huffman, JPEG, CCITT Group 3, CCITT Group 4 and PackBits. The MIME type associated with this fax format is image/g3fax.
The .g3f extension is associated with Zetafax fax files rather than general-purpose image files, so other image applications may not recognize the file directly.
Open the file with Zetafax on Microsoft Windows to view its fax content.
Generic image viewers may not open a .g3f file even though the fax data is TIFF-based.
Open the file in Zetafax and use the software's available export or print functions to create a more widely supported document. Printing to PDF on Windows is a practical option when an editable image export is not available.
Direct conversion by a general-purpose image converter is not guaranteed because the file is intended for Zetafax. Do not assume that changing the extension alone converts the file.
Programs for viewing g3f files:
Microsoft Windows
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