CFF to FAX Converter

Render CFF font data into fax-compatible raster images online

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Fax-Ready Output

The conversion produces monochrome images in fax-compatible format from CFF font data — ready for direct transmission through fax systems.

Browser-Based

No fax software or image processing tools needed — run the CFF to FAX conversion from any web browser on any device.

Quick Processing

Convertio servers render CFF outlines to FAX format rapidly, delivering your output in seconds with no local resources consumed.

How to convert CFF to FAX

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose fax or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your fax file right afterwards

About formats

CFF (Compact Font Format) is a font outline format developed by Adobe Systems around 1996 as a more efficient successor to the Type 1 font representation. CFF uses Type 2 charstrings — an optimized encoding that supports multiple arguments per operator, default value elision, and shared subroutines — to describe the same cubic Bezier glyph outlines as Type 1 but with substantially less storage. A typical CFF font is 20-50% smaller than its Type 1 equivalent. The format can function as a standalone font file or, more commonly, as the outline data table inside an OpenType font container (the CFF table in OTF files with PostScript outlines). CFF supports multiple fonts within a single file through its FontSet structure, sharing global subroutines across the collection to further reduce size. One advantage is compression efficiency without lossy degradation — every control point and hint is preserved exactly, just encoded more compactly. The format also inherits the full hinting capability of Type 1, including stem hints, counter hints, and alignment zones that ensure crisp rendering on low-resolution screens and printers. CFF2, an evolution introduced with OpenType 1.8, adds support for font variations (variable fonts) by allowing interpolation across multiple design axes. Broad support in PDF viewers, web browsers via OpenType, and professional design software makes CFF one of the most widely deployed outline formats in digital typography.
Developer: Adobe Systems
Initial release: 1996
FAX is a generic image file extension associated with facsimile transmission formats standardized by the ITU-T (formerly CCITT), with the underlying Group 3 compression standard ratified in 1980. FAX files typically contain monochrome (1-bit, black and white) image data compressed using the Modified Huffman (MH) encoding defined in ITU-T Recommendation T.4, which assigns variable-length codes to run lengths of consecutive white or black pixels along each scanline. The standard resolution for Group 3 fax is 204x98 dpi (normal mode) or 204x196 dpi (fine mode), reflecting the capabilities of thermal and laser fax machines of the era. FAX files encountered digitally are often raw Group 3 encoded bitstreams or TIFF wrappers with CCITT Group 3 compression (TIFF compression tag 3). The Group 3 encoding scheme is highly efficient for typical business documents — pages with mostly white space and black text — achieving compression ratios of 10:1 to 20:1 compared to uncompressed bitmaps. One advantage is universal fax system compatibility: Group 3 encoding is the mandatory baseline for all fax machines worldwide, meaning FAX files contain data in exactly the format transmitted over telephone lines, preserving the original fax data without transcoding losses. The format's role in business communications history provides another dimension — billions of fax transmissions using this encoding moved legal documents, medical records, and business correspondence for decades, and archived FAX files represent an important documentary record. FAX images can be viewed and converted using LibreOffice, ImageMagick, GIMP, and standard document management systems.
Developer: ITU-T
Initial release: 1980

Frequently Asked Questions

Why convert CFF to FAX?

FAX format produces monochrome images optimized for fax transmission — useful when font renderings need to be sent via legacy fax systems or fax-over-IP services.

How do I open a FAX file?

Windows Fax Viewer, IrfanView, and GIMP all open FAX-format images. Fax server software and multifunction printers also process this format directly.

Is the output monochrome?

Yes — fax format uses Group 3 compression on monochrome data. Font glyphs are rendered in black and white, optimized for fax-resolution output.

Can I fax the result directly?

The FAX-format image is compatible with fax machines and fax software. Upload it to a fax service or feed it to your fax modem for transmission.

Is CFF to FAX free?

Yes — Convertio handles CFF to FAX conversion at no charge, entirely in the cloud from your browser.