CFF to G4 Converter

Render CFF font outlines as Group 4 fax compressed images online

Drop files here. 1 GB maximum file size or Sign Up
to
Facebook Amazon Microsoft Tesla Nestle Walmart L'Oreal

Document Standard

Group 4 is the industry standard for document archival and high-speed fax. CFF to G4 conversion produces highly compressed monochrome glyph images.

Quick Processing

Server-side rendering produces compact G4 output from CFF fonts in seconds — fast results without burdening your local machine.

Secure Files

Uploaded CFF fonts are deleted immediately and G4 results are purged within 24 hours for complete data privacy.

How to convert CFF to G4

1

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

2

Choose g4 or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your g4 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
G4 is a monochrome image format based on the ITU-T Group 4 facsimile coding standard (Recommendation T.6), ratified by the CCITT in 1984 as an improvement over Group 3 for use on error-free digital networks like ISDN rather than analog telephone lines. G4 files contain 1-bit image data compressed using exclusively two-dimensional Modified Modified READ (MMR) coding, where each scanline is encoded as a set of differences (changing elements) relative to the line above it. By eliminating the one-dimensional coding fallback and the end-of-line synchronization markers required by Group 3, G4 achieves 20-50% better compression ratios on typical document pages while producing a simpler, more regular bitstream. The format is most commonly encountered as a compression method within TIFF files (TIFF compression tag 4), where it became the standard archival format for scanned documents in enterprise document management, government records, and legal imaging systems. G4 compression is specified at 200, 300, or 400 dpi depending on the scanning application, with 300 dpi being the most common for archival-quality document imaging. One advantage is exceptional compression efficiency for document content: G4's two-dimensional prediction exploits the strong vertical correlation in text and line art pages, typically compressing a 300 dpi letter-size page to 30-50 KB — roughly half the size of equivalent Group 3 encoding. The format's entrenchment in document management infrastructure is another strength — G4 TIFF is the mandated format for many government digital records systems, court filing systems, and corporate archives, supported by every enterprise imaging platform.
Developer: ITU-T (CCITT)
Initial release: 1984

Frequently Asked Questions

Why convert CFF to G4?

CCITT Group 4 offers better compression than Group 3 for bi-level images. It is widely used in document management, archival, and high-speed fax systems.

How do I open a G4 file?

G4 images are supported by IrfanView, GIMP, ImageMagick, and document management systems. They can also be embedded in TIFF containers for broader compatibility.

Is G4 better than G3?

Yes — Group 4 achieves higher compression ratios than Group 3 because it uses two-dimensional coding. It is the preferred standard for document archival.

Is the output monochrome?

Yes — Group 4 is a bi-level compression scheme. CFF glyphs are rendered as black on white, optimized for document storage and fax transmission.

Is CFF to G4 free?

Entirely free on Convertio — no downloads, no account, just browser-based conversion in seconds.