Image MIME Reference
EDMICS-RLC
Fuji Xerox EDMICS-RLC
image/vnd.fujixerox.edmics-rlc
VS
Portable Graymap
image/x-portable-graymap
PGM
A complete technical comparison of Fuji Xerox EDMICS-RLC and Portable Graymap — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | EDMICS-RLC | PGM |
|---|---|---|
| Transparency (Alpha) | ✕ No | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | ✕ No | Yes |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | ✕ No | ✕ No |
Fuji Xerox EDMICS-RLC
image/vnd.fujixerox.edmics-rlc
Extension
.rlc.edm
Container
Fuji Xerox EDMICS Wrapper
Compression
Run-Length Coding (RLC / RLE)
Algorithm
Run-Length Coding (RLC)
Color Depth
1-bit (Monochrome), 8-bit (Grayscale)
Developed by
Fuji Xerox Co., Ltd.
Released
1990s
Magic Bytes
Unknown (Proprietary Container)
Portable Graymap
image/x-portable-graymap
Extension
.pgm
Container
Netpbm
Compression
Uncompressed
Algorithm
None
Color Depth
8-bit (Grayscale), 16-bit (Grayscale)
Developed by
Jef Poskanzer (Netpbm Project)
Released
1988
Magic Bytes
50 32 (ASCII) or 50 35 (Binary)
Browser Support Comparison
| Browser | EDMICS-RLC | PGM |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
EDMICS-RLC
EDMICS-RLC Strengths
- Simple, computationally inexpensive Run-Length Coding enabled rapid compression and decompression on low-power legacy hardware
- Deeply integrated into Fuji Xerox enterprise hardware for seamless, automated 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 viewers without bespoke decoding tools
- RLC compression is far less efficient than modern algorithms like PNG (Deflate) for complex documents
PGM
PGM Strengths
- Extremely simple format allows custom parsers to be written from scratch in minimal time
- Supports 16-bit precision, making it highly valuable for scientific, medical, and height-map data where 8-bit precision is insufficient
- ASCII encoding ('P2') allows manual editing and visual inspection of pixel values directly within a text editor
Limitations
- Strictly limited to grayscale; cannot display color
- Lack of compression results in massive file sizes, making it entirely impractical for web delivery or consumer storage
- Does not support alpha transparency or modern metadata structures
When to choose which format
EDMICS-RLC
Use EDMICS-RLC when…
- Fuji Xerox EDMICS Enterprise Systems
- Archival of Scanned Engineering Documents
- Legacy Corporate Scanning Pipelines
PGM
Use PGM when…
- Computer Vision and Machine Learning Pre-processing
- Scientific and Medical Image Processing
- Unix/Linux Command-Line Image Pipelines