Image MIME Reference
ACES
ACES Image Container File
image/aces
VS
MicroStation Design File
image/x-vnd.dgn
DGN
A complete technical comparison of ACES Image Container File and MicroStation Design File — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | ACES | DGN |
|---|---|---|
| Transparency (Alpha) | Yes | Yes |
| 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
MicroStation Design File
image/x-vnd.dgn
Extension
.dgn
Container
Microsoft OLE Compound File (V8) / IGDS (V7)
Compression
Uncompressed / OLE Structured Storage
Algorithm
None
Color Depth
Indexed Color (V7), 24-bit True Color (V8)
Developed by
Intergraph (Originally) / Bentley Systems (Currently)
Released
1980
Magic Bytes
D0 CF 11 E0 A1 B1 1A E1 (For V8 DGN)
Browser Support Comparison
| Browser | ACES | DGN |
|---|---|---|
|
|
✕ | ✕ |
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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
DGN
DGN Strengths
- Exceptionally robust at handling massive, coordinate-heavy infrastructure models that would frequently crash older versions of competing CAD software
- Deeply entrenched as the absolute standard format for many global departments of transportation and civil engineering firms
- V8 architecture supports boundless design plane coordinates, eliminating the physical scaling limitations of V7
Limitations
- Deeply proprietary format requiring complex third-party libraries (like the ODA SDK) to parse or write programmatically outside of the Bentley ecosystem
- V8's reliance on the archaic Microsoft OLE Compound File container makes file introspection cumbersome
- Cannot be rendered natively in web browsers without converting to WebGL/Canvas formats or SVG
When to choose which format
ACES
Use ACES when…
- Visual Effects (VFX)
- Digital Intermediate (DI)
- Color Grading
- Archival
DGN
Use DGN when…
- Civil Engineering and Plant Design
- Large-scale Architecture and Construction (AEC)
- 2D/3D Infrastructure Modeling