Image MIME Reference
Epson-ERF
Epson Raw Format
image/x-epson-erf
VS
JPEG 2000 Image (HEIF Container)
image/hej2k
HEJ2K
A complete technical comparison of Epson Raw Format and JPEG 2000 Image (HEIF Container) — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | Epson-ERF | HEJ2K |
|---|---|---|
| Transparency (Alpha) | ✕ No | Yes |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | Yes |
| HDR Support | Yes | Yes |
| EXIF Metadata | Yes | Yes |
| ICC Color Profile | ✕ No | Yes |
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
JPEG 2000 Image (HEIF Container)
image/hej2k
Extension
.hej2
Container
HEIF / ISOBMFF (ISO/IEC 15444-16)
Compression
Lossy / Lossless
Algorithm
JPEG 2000HTJ2K
Color Depth
8-bit, 10-bit, 12-bit, 16-bit
Developed by
ISO/IEC JTC 1 / ITU-T
Released
2019
Magic Bytes
XX XX XX XX 66 74 79 70 6A 32 6B 69
Browser Support Comparison
| Browser | Epson-ERF | HEJ2K |
|---|---|---|
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
HEJ2K
HEJ2K Strengths
- Brings the extensive capabilities of the HEIF container (like EXIF/XMP, thumbnails, and depth maps) to JPEG 2000
- Supports mathematically lossless compression via wavelet transformation
- High scalability and progressive decoding out of the box
Limitations
- Extremely limited software support outside of niche industries
- Zero native compatibility with web browsers
- High computational complexity compared to simpler formats like JPEG or PNG
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
HEJ2K
Use HEJ2K when…
- Medical Imaging
- Geospatial Data
- Scientific Archiving