LRF to G4 Converter

Convert LRF ebooks to Group 4 FAX format — free

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LRF to Fax-Ready G4

Convert discontinued Sony Reader ebooks into Group 4 FAX images — lossless bi-level compression ideal for document archival.

Lossless Compression

G4 preserves every pixel without quality degradation. Text-heavy LRF ebook pages compress efficiently while staying perfectly sharp.

Cloud-Based Engine

Convertio processes everything server-side. No special software on your device — just upload LRF and collect G4 output.

How to convert LRF 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

LRF is the file format associated with Sony's BBeB (Broadband eBook) specification, jointly developed by Sony and Canon and introduced in 2004 with the Sony Librie EBR-1000EP — the world's first commercial E Ink e-reader. The format supports both reflowable text and fixed-layout page rendering, embedding fonts, images, vector graphics, and metadata within a compact binary container. LRF files use a block-based internal structure with object trees describing page layouts, text streams, image resources, and table of contents navigation. Sony's Reader devices and the companion desktop software (Sony Reader Library) served as the primary ecosystem for LRF content throughout the mid-2000s. A key advantage was its early adoption of high-quality font embedding and text rendering optimized specifically for E Ink displays, delivering a reading experience noticeably superior to many competing formats of the era. The format also supported bookmark synchronization, dictionary lookups, and annotations within the Sony Reader ecosystem. However, Sony officially discontinued BBeB/LRF support in 2010, migrating its Reader platform to the industry-standard EPUB format. Today LRF files are primarily encountered in personal ebook collections from that period and can be converted to modern formats using tools like Calibre. The format remains a historically significant milestone as the native format of the device category that launched the modern e-reader revolution.
Developer: Sony
Initial release: 2004
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 LRF to G4?

G4 uses ITU Group 4 compression for bi-level images — perfect for archiving text-heavy LRF pages as compact, fax-compatible document images.

What can open G4 files?

IrfanView, XnView, Adobe Acrobat, LibreOffice Draw, and most document imaging systems support Group 4 TIFF/FAX images natively.

Is G4 lossy or lossless?

G4 compression is completely lossless. Every pixel of your rendered LRF page is preserved exactly in the output file.

How compact are G4 files?

Very compact for text content. Group 4 compression was designed for documents and excels at shrinking black-and-white page images.

Does this cost anything?

No, LRF to G4 conversion is free on Convertio. Premium plans add higher volume limits and priority processing for power users.