What is the SFW file format?
.sfw is an older graphics format. Files with the .sfw extension contain raster images created by Seattle FilmWorks, a US mail-order photographic film processing company active in the 1990s. The company digitized customers' 35mm film rolls and returned the scans as .sfw files on floppy disks or CDs, together with a dedicated viewer program. SFW files contain the converted film frames at typical scanning resolutions of 800×600 to 1600×1200 pixels.
Technically, .sfw is a JPEG-derivative format. All known variants - SFW93A (1993), SFW94A (most common, circa 1994-2000), and SFW98A (1998) - consist of an approximately 200-byte proprietary header prepended to standard JPEG image data. Because SFW is based on JPEG, conversion is effectively lossless: stripping the header recovers a valid JPEG with no re-encoding needed. Seattle FilmWorks later rebranded as PhotoWorks and retired the SFW format around 2003.
Seattle FilmWorks software disappeared from the market at the turn of the 21st century, so .sfw files are very rarely encountered today. SFW is a proprietary format, but some modern image editors are capable of opening such files. A reliable solution is the dedicated SFW & PWP File Converter freeware (available at jonesrh.info), which extracts .jpg images from SFW data without any quality loss.
Security & safety
RISK: LOWObsolete image format; no known active exploits. Files originate from a specific 1990s service, so provenance is usually clear. Standard JPEG safety considerations apply.
Format details
in a nutshellPrograms that open SFW files
Windows4 apps
SFW PhotoWorks (jonesrh.info converter)
Free Download SFWJPG or SFW & PWP File Converter; drag SFW files onto the tool to batch-convert to JPG.
File Viewer Plus
Paid Open SFW directly from File Viewer Plus; supports view and export to common image formats. 
macOS2 apps
Technical details
deep spec| Format type | Proprietary raster image (JPEG-derivative with custom header) |
| Developer | Seattle FilmWorks Inc. (later rebranded as PhotoWorks) |
| MIME type | image/x-sfw |
| Known format variants | SFW93A (1993), SFW94A (most common, ~1994-2000), SFW98A (1998) |
| Magic bytes | 6-byte ASCII signature at offset 0: SFW93A, SFW94A, or SFW98A depending on variant |
| Header size | Approximately 200 bytes proprietary header preceding JPEG image data |
| Image encoding | JPEG (DCT lossy compression) |
| Color depth | 24 bpp (RGB, standard JPEG) |
| Typical scan dimensions | 800×600 to 1600×1200 px (1990s 35mm film digitization) |
| Typical file size | 100 KB - 1.5 MB |
| JPEG conversion | Lossless header-strip only; no re-encoding required |
| Companion format | .pwp (PhotoWorks PhotoMail) |
| Platform | Windows; Mac OS (classic) |
| Superseded by | JPEG (SFW format retired by PhotoWorks circa 2003) |
| Released | 1993 (SFW93A earliest known variant) |
| Latest version | SFW98A (1998 variant, last known) |
| Specification | jonesrh.info |
SFW conversions
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