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Image MIME Reference
PWG-Raster

PWG Raster Format

image/pwg-raster
VS

SealedMedia SoftSeal JPEG

image/vnd.sealedmedia.softseal.jpg
SoftSeal-JPEG

A complete technical comparison of PWG Raster Format and SealedMedia SoftSeal JPEG — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature PWG-Raster SoftSeal-JPEG
Transparency (Alpha) ✕ No ✕ No
Animation Support ✕ No ✕ No
Progressive Loading ✕ No ✕ No
HDR Support ✕ No ✕ No
EXIF Metadata ✕ No ✕ No
ICC Color Profile ✕ No ✕ No
PWG Raster Format
image/pwg-raster
Extension
.pwg.ras
Container CUPS Raster v2 Container
Compression PackBits (Run-Length Encoding)
Algorithm
PackBits (Apple RLE variant)
Color Depth 1-bit (Monochrome/K), 8-bit (Grayscale), 24-bit (sRGB / Adobe RGB), 32-bit (CMYK)
Developed by IEEE-ISTO Printer Working Group (PWG)
Released 2011
Magic Bytes
52 61 53 32
Full PWG-Raster reference →
SealedMedia SoftSeal JPEG
image/vnd.sealedmedia.softseal.jpg
Extension
.sjpg.sealed-jpg.sealed-jpeg
Container SealedMedia SoftSeal Wrapper
Compression Encrypted Payload (DCT)
Algorithm
AES EncryptionDiscrete Cosine Transform (Internal JPEG payload)
Color Depth Encrypted Payload (Historically 24-bit RGB)
Developed by SealedMedia (Acquired by Oracle Corporation)
Released Late 1990s
Magic Bytes
Unknown (Proprietary SealedMedia Container)
Full SoftSeal-JPEG reference →

Browser Support Comparison

Browser PWG-Raster SoftSeal-JPEG
Chrome Chrome
✕ ✕
Firefox Firefox
✕ ✕
Safari Safari
✕ ✕
Edge Edge
✕ ✕
IE IE (Legacy)
✕ ✕
PWG-Raster

PWG-Raster Strengths

  • The undisputed global standard for modern, driverless printing environments, eliminating the nightmare of installing manufacturer-specific print drivers
  • Extremely lightweight to decode on embedded hardware, requiring minimal RAM buffers on the printer side
  • Strict color space and resolution rules guarantee that the printed output will successfully process without syntax errors
Limitations
  • Generates massive file sizes and network payloads compared to vector-based formats like PDF or PostScript, as every page is fully rasterized at 300+ DPI before transmission
  • No support for native rendering in web browsers, image viewers, or graphic design software without specialized CUPS developer tools
  • Cannot store complex metadata, vector text, or layers
SoftSeal-JPEG

SoftSeal-JPEG Strengths

  • Offered persistent document security; if a sensitive photo was emailed outside the company, it remained encrypted and unviewable without server authentication
  • Administrators possessed the ability to remotely revoke viewing rights to a specific image globally at any time
Limitations
  • Completely proprietary and relies on a central authentication server; if the server goes offline or the product is deprecated, the image is permanently inaccessible
  • Zero support in modern operating systems, web browsers, or standard image editing suites without heavy enterprise client installations
  • Oracle effectively discontinued the IRM product line, stranding many legacy sealed documents

When to choose which format

PWG-Raster
Use PWG-Raster when…
  • Driverless Network Printing (IPP Everywhere)
  • Apple AirPrint and Mopria Print Service Pipelines
  • CUPS (Common UNIX Printing System) Spooling
SoftSeal-JPEG
Use SoftSeal-JPEG when…
  • Enterprise Information Rights Management (IRM)
  • Secure Distribution of Sensitive Photography
  • Revocable Corporate Document Access

More comparisons

PWG-Raster vs ACES → SoftSeal-JPEG vs ACES → PWG-Raster vs APNG → SoftSeal-JPEG vs APNG → PWG-Raster vs AVCI → SoftSeal-JPEG vs AVCI → PWG-Raster vs AVCS → SoftSeal-JPEG vs AVCS → PWG-Raster vs AVIF → SoftSeal-JPEG vs AVIF → All comparisons →
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