Image MIME Reference
EDMICS-MMR
Fuji Xerox EDMICS-MMR
image/vnd.fujixerox.edmics-mmr
VS
Pentax Electronic File
image/x-pentax-pef
Pentax-PEF
A complete technical comparison of Fuji Xerox EDMICS-MMR and Pentax Electronic File — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | EDMICS-MMR | Pentax-PEF |
|---|---|---|
| Transparency (Alpha) | ✕ No | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | ✕ No | Yes |
| EXIF Metadata | ✕ No | Yes |
| ICC Color Profile | ✕ No | Yes |
Fuji Xerox EDMICS-MMR
image/vnd.fujixerox.edmics-mmr
Extension
.mmr.edm
Container
Fuji Xerox EDMICS Wrapper
Compression
Modified Modified READ (MMR / Group 4 Fax)
Algorithm
MMR (ITU-T T.6 / CCITT Group 4)
Color Depth
1-bit (Monochrome / Bi-level)
Developed by
Fuji Xerox Co., Ltd.
Released
1990s
Magic Bytes
Unknown (Proprietary Container wrapped around MMR bitstream)
Pentax Electronic File
image/x-pentax-pef
Extension
.pef
Container
TIFF-based (Proprietary)
Compression
Uncompressed / Proprietary Lossless
Algorithm
NonePentax Proprietary Lossless
Color Depth
12-bit (Per Channel), 14-bit (Per Channel)
Developed by
Pentax (now Ricoh Imaging Company, Ltd.)
Released
2003
Magic Bytes
49 49 2A 00 (Little-endian) or 4D 4D 00 2A (Big-endian)
Browser Support Comparison
| Browser | EDMICS-MMR | Pentax-PEF |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
EDMICS-MMR
EDMICS-MMR Strengths
- Utilized the highly efficient MMR (Group 4) algorithm, which allowed massive, E-size engineering blueprints to be compressed into tiny file sizes suitable for 1990s hard drives and networks
- Deeply integrated into Fuji Xerox hardware and database systems for seamless scan-to-archive workflows
Limitations
- Completely proprietary and closed-source, making modern archival extraction and migration extremely difficult
- No support in modern image processing libraries like ImageMagick, libvips, or standard TIFF viewers without first stripping the proprietary header
- Strictly limited to 1-bit monochrome images
Pentax-PEF
Pentax-PEF Strengths
- Retains absolute maximum sensor data, enabling massive shadow recovery and highlight protection compared to compressed in-camera JPEGs
- White balance and sharpening are saved as metadata instructions rather than 'baked in', meaning they can be perfectly adjusted in post-production
- Utilizes the standard TIFF container structure, making it relatively straightforward for open-source software like LibRaw to parse
Limitations
- Proprietary format requires continuous updates to third-party processing software whenever Pentax releases a new camera model (unlike the open DNG format)
- Produces very large file sizes compared to standard web formats
- Cannot be directly embedded into web pages or used in standard HTML/CSS contexts
When to choose which format
EDMICS-MMR
Use EDMICS-MMR when…
- Fuji Xerox EDMICS Enterprise Systems
- Archival of Large-Format Engineering Drawings
- Legacy Corporate Document Scanning Pipelines
Pentax-PEF
Use Pentax-PEF when…
- Professional Digital Photography
- Non-destructive Image Post-Processing
- Pentax Camera Archival