Image MIME Reference
PWG-Raster
PWG Raster Format
image/pwg-raster
VS
Pixologic ZBrush PCX
image/vnd.zbrush.pcx
ZBrush-PCX
A complete technical comparison of PWG Raster Format and Pixologic ZBrush PCX — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | PWG-Raster | ZBrush-PCX |
|---|---|---|
| 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
Pixologic ZBrush PCX
image/vnd.zbrush.pcx
Extension
.pcx
Container
ZSoft PCX
Compression
Run-Length Encoding (RLE)
Algorithm
ZSoft Run-Length Encoding (RLE)
Color Depth
8-bit (Grayscale), 24-bit (RGB)
Developed by
ZSoft (Format) / Pixologic (MIME Registration)
Released
1985
Magic Bytes
0A 05 01 08
Browser Support Comparison
| Browser | PWG-Raster | ZBrush-PCX |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
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
ZBrush-PCX
ZBrush-PCX Strengths
- Extremely simple, lossless RLE compression makes it trivial to parse and encode programmatically
- Universally supported by almost every 2D image editor created since the 1990s
Limitations
- Completely obsolete for modern 3D workflows, which require 16-bit or 32-bit floating-point precision (like OpenEXR or TIFF) to avoid stepping artifacts in displacement maps
- No support for modern metadata (EXIF/XMP) or native alpha channels
- Zero native support in modern web browsers
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
ZBrush-PCX
Use ZBrush-PCX when…
- Legacy ZBrush Alpha Brushes
- 8-bit Grayscale Displacement Maps
- ZBrush Texture Exports