There are at least three different SFW formats, and one PWP format. The are also at least two other related formats that don't directly contain images: .pwm and .alb.
||It's not clear if this format was ever used.|
|"SFW94A" SFW, compressed||
||Based on JPEG. The most widely supported format.|
|"SFW94A" SFW, uncompressed||Based on BMP.|
|.pwm||Not an image format.|
||Container format for multiple SFW images.|
||Based on JPEG with arithmetic coding. Caution: Some utilities reportedly extract only the thumbnail image.|
||Not an image format.|
Files begin with an ASCII signature (see the Formats section), but it's not always sufficient to determine the specific format.
The sfwwhichfmt.c utility listed in the Software section below may be helpful.
- jonesrh .sfw conversion portal - Has information about conversion software
- sfwwhichfmt.c - Utility to display information about SFW/PWP files.
- File format conversion software for Seattle FilmWorks products → sfwjpg-unix.tar (from archive.org)
- SFWJPG (Windows version of sfwjpg-unix.tar)