Image MIME Reference
MacPaint
MacPaint Image
image/x-macpaint
VS
Sigma X3F RAW Image
image/x-sigma-x3f
Sigma-X3F
A complete technical comparison of MacPaint Image and Sigma X3F RAW Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | MacPaint | Sigma-X3F |
|---|---|---|
| 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 |
MacPaint Image
image/x-macpaint
Extension
.mac.pntg.pnt.macp
Container
Raw pixel payload with a 512-byte pattern header
Compression
PackBits (Run-Length Encoding)
Algorithm
PackBits (Apple RLE)
Color Depth
1-bit (Monochrome)
Developed by
Apple Computer, Inc. (Bill Atkinson)
Released
1984
Magic Bytes
None (Relies on classic Mac OS 'PNTG' OSType)
Sigma X3F RAW Image
image/x-sigma-x3f
Extension
.x3f
Container
Foveon Proprietary Header
Compression
Uncompressed / Proprietary Lossless
Algorithm
NoneFoveon Proprietary Huffman-based
Color Depth
12-bit (Per Channel), 14-bit (Per Channel)
Developed by
Foveon, Inc. / Sigma Corporation
Released
2002
Magic Bytes
46 4F 56 62
Browser Support Comparison
| Browser | MacPaint | Sigma-X3F |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
MacPaint
MacPaint Strengths
- Profoundly historically significant as the format that introduced millions to the concept of bitmap digital painting
- Extremely simple PackBits compression makes it easy for emulator developers or archivists to write parsers from scratch in under an hour
Limitations
- Severely limited: strictly black and white, and hard-locked to exactly 576 x 720 pixels
- Lack of standard magic bytes makes programmatic file sniffing unreliable on modern filesystems without relying on the file extension
- Completely obsolete and unsupported by modern web browsers or consumer image viewers
Sigma-X3F
Sigma-X3F Strengths
- Provides absolute per-pixel color accuracy without the interpolation artifacts or moiré patterns typical of Bayer-sensor RAW files
- Unique 'FOVb' magic byte signature prevents accidental misidentification by standard file sniffers, unlike many TIFF-based raw formats
- Incredible sharpness and detail resolution at the raw sensor level
Limitations
- Decoding is extremely computationally expensive and completely proprietary, meaning third-party software often struggles to match the color science of Sigma's own (famously slow) Photo Pro application
- Massive file sizes because it records three complete RGB channels for every single spatial pixel coordinate
- Zero support in web browsers or standard OS image viewers
When to choose which format
MacPaint
Use MacPaint when…
- Historical Apple Macintosh Archival
- Early 1980s Digital Art Preservation
- Retro UI/UX Academic Research
Sigma-X3F
Use Sigma-X3F when…
- Professional Digital Photography
- Sigma / Foveon High-Acuity Imaging
- Non-destructive RAW Post-Processing