Image MIME Reference
Epson-ERF
Epson Raw Format
image/x-epson-erf
VS
Pixologic ZBrush PCX
image/vnd.zbrush.pcx
ZBrush-PCX
A complete technical comparison of Epson Raw 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 | Epson-ERF | ZBrush-PCX |
|---|---|---|
| Transparency (Alpha) | ✕ No | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | ✕ No |
| EXIF Metadata | Yes | ✕ No |
| ICC Color Profile | ✕ No | ✕ No |
Epson Raw Format
image/x-epson-erf
Extension
.erf
Container
TIFF/EP
Compression
Uncompressed / Lossless JPEG (ITU-T81)
Algorithm
NoneLossless JPEG
Color Depth
12-bit (Per Channel)
Developed by
Seiko Epson Corporation
Released
2004
Magic Bytes
49 49 2A 00 or 4D 4D 00 2A
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 | Epson-ERF | ZBrush-PCX |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
Epson-ERF
Epson-ERF Strengths
- Preserves original raw sensor data, allowing extreme recovery of highlights and shadows compared to in-camera JPEGs
- Utilizes the standard TIFF container structure, making it relatively easy for open-source software (like dcraw and LibRaw) to parse and decode
Limitations
- Completely obsolete proprietary format tied to a defunct line of digital cameras
- Requires parsing EXIF metadata to differentiate it from standard TIFF files programmatically
- Cannot be natively viewed in web browsers or standard operating system image viewers without specialized codecs
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
Epson-ERF
Use Epson-ERF when…
- Vintage Digital Photography (Epson R-D1)
- Non-destructive Image Post-Processing
- Raw Imaging Archival
ZBrush-PCX
Use ZBrush-PCX when…
- Legacy ZBrush Alpha Brushes
- 8-bit Grayscale Displacement Maps
- ZBrush Texture Exports