Image MIME Reference
ACES
ACES Image Container File
image/aces
VS
MacPaint Image
image/x-macpaint
MacPaint
A complete technical comparison of ACES Image Container File and MacPaint Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | ACES | MacPaint |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | ✕ No |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | ✕ No | ✕ No |
ACES Image Container File
image/aces
Extension
.exr
Container
OpenEXR (SMPTE ST 2065-4)
Compression
Lossless / Uncompressed
Algorithm
PIZZIPRLEB44Uncompressed
Color Depth
16-bit (Half-float), 32-bit (Float)
Developed by
Academy of Motion Picture Arts and Sciences (AMPAS) / SMPTE
Released
2013
Magic Bytes
76 2F 31 01
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)
Browser Support Comparison
| Browser | ACES | MacPaint |
|---|---|---|
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✕ | ✕ |
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✕ | ✕ |
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✕ | ✕ |
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✕ | ✕ |
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✕ | ✕ |
ACES
ACES Strengths
- Industry standard for high-end visual effects, compositing, and color grading
- Supports 16-bit half-float data, accurately capturing immense dynamic range without clipping
- Standardized by SMPTE (ST 2065-4) to guarantee universal color interoperability across different post-production facilities
Limitations
- Considerably larger file sizes than conventional consumer image formats
- Completely unsupported in web browsers and most standard desktop viewers
- Requires specialized compositing or color grading software to interpret and view the scene-linear data correctly
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
When to choose which format
ACES
Use ACES when…
- Visual Effects (VFX)
- Digital Intermediate (DI)
- Color Grading
- Archival
MacPaint
Use MacPaint when…
- Historical Apple Macintosh Archival
- Early 1980s Digital Art Preservation
- Retro UI/UX Academic Research