SFW to G4 Converter

Export SFW photographs to G4 format online for free

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No Install Required

The entire SFW to G4 conversion runs in your browser. No desktop software, no plugins — just upload and convert.

Private & Secure

Your SFW uploads are deleted right after conversion, and the G4 output is removed from servers within 24 hours — your data stays safe.

Memory Recovery

Those old Seattle FilmWorks photos deserve to be seen. Converting SFW to G4 brings your personal photographs back to life.

How to convert SFW 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

SFW is a proprietary image format created by Seattle FilmWorks (later PhotoWorks) for their Pictures on Disk mail-order photo service, active primarily from 1994 through the early 2000s. Customers who sent film to Seattle FilmWorks for developing could opt to receive their photos back on 3.5-inch floppy disks in addition to (or instead of) traditional prints. SFW files contained the scanned photographs in a JPEG-based encoding wrapped in a custom header, designed to be viewed through Seattle FilmWorks' proprietary desktop software. The service was notably popular in the mid-1990s, offering one of the most accessible ways for ordinary consumers to obtain digital versions of their film photographs before consumer scanners and digital cameras became affordable. SFW files typically contained modest-resolution scans appropriate for screen viewing and small prints — sufficient quality for the 640x480 and 800x600 monitor resolutions common at the time. One advantage of SFW files is their role as historical artifacts: for many families, SFW disks represent the only digital copies of film-era photographs from the 1990s, preserved on media that predates widespread home scanning and digital photography. The underlying JPEG data ensures reasonable image quality despite the proprietary wrapper. Extracting images from SFW files is straightforward: tools like XnView, ImageMagick, and specialized SFW-to-JPEG converters can strip the proprietary header and save the standard JPEG data, making these nostalgic files accessible on any modern device.
Developer: Seattle FilmWorks
Initial release: 1994
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 SFW to G4?

SFW photos require viewer software that no longer ships. Converting to G4 ensures those memories remain viewable and shareable.

What programs can open G4?

Fax software, IrfanView, and ImageMagick open Group 4 fax images. This compression standard is used in high-resolution fax and TIFF.

Is the conversion from SFW to G4 lossless?

Since G4 supports lossless storage, the pixel data carries over without degradation. The result faithfully represents the source SFW image.

How quickly can I convert SFW to G4?

Most SFW images convert to G4 within seconds. The exact time depends on the resolution and complexity of the source, but it is typically quick.

Can I queue several SFW files for conversion?

Batch conversion is supported. Queue as many SFW files as you need and convert them all to G4 in a single run — no repeating steps manually.