Image MIME Reference
KTX2
Khronos Texture 2.0
image/ktx2
VS
Nikon Electronic Format
image/x-nikon-nef
Nikon-NEF
A complete technical comparison of Khronos Texture 2.0 and Nikon Electronic Format — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | KTX2 | Nikon-NEF |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | Yes |
| EXIF Metadata | ✕ No | Yes |
| ICC Color Profile | ✕ No | Yes |
Khronos Texture 2.0
image/ktx2
Extension
.ktx2
Container
KTX 2.0
Compression
Basis Universal (ETC1S / UASTC) / Zstandard (zstd) Supercompression / Uncompressed
Algorithm
ETC1SUASTCZstandard (zstd)Raw GPU Formats (ASTC, BCn)
Color Depth
8-bit, 16-bit, 32-bit (Float)
Developed by
Khronos Group
Released
2021
Magic Bytes
AB 4B 54 58 20 32 30 BB 0D 0A 1A 0A
Nikon Electronic Format
image/x-nikon-nef
Extension
.nef
Container
TIFF
Compression
Uncompressed / Lossless Compressed / Lossy Compressed (High Efficiency)
Algorithm
NoneNikon Proprietary LosslessNikon High Efficiency Lossy
Color Depth
12-bit (Per Channel), 14-bit (Per Channel)
Developed by
Nikon Corporation
Released
1999
Magic Bytes
49 49 2A 00 or 4D 4D 00 2A
Browser Support Comparison
| Browser | KTX2 | Nikon-NEF |
|---|---|---|
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✕ | ✕ |
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✕ | ✕ |
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✕ | ✕ |
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|
✕ | ✕ |
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|
✕ | ✕ |
KTX2
KTX2 Strengths
- Universal hardware compatibility: write once, transcode anywhere to the target GPU's preferred format (ASTC, BC7, PVRTC, etc.)
- Drastically reduces transmission size over networks thanks to Basis Universal and Zstandard supercompression
- Seamless integration with the glTF ecosystem for optimized 3D asset delivery
Limitations
- Requires WebAssembly (Wasm) decoders and JavaScript loaders for web viewing, increasing initial application payload slightly
- Encoding textures into high-quality Basis Universal UASTC can be computationally intensive and slow
- Zero support in traditional 2D image viewers or native OS previews
Nikon-NEF
Nikon-NEF Strengths
- Retains maximum sensor data, allowing extreme recovery of highlights and shadows that would be permanently lost in a JPEG
- White balance, sharpening, and color profiling are saved as metadata instructions rather than 'baked in', meaning they can be completely altered in post-production without degrading the image
- Embeds a high-quality JPEG preview inside the raw file for rapid culling and viewing
Limitations
- Proprietary format means it requires constant updates to raw processing engines every time Nikon releases a new camera model
- Produces very large file sizes (often 20MB to 50MB+ per image depending on sensor resolution and bit-depth)
- Cannot be directly embedded into web pages or used in standard HTML/CSS contexts
When to choose which format
KTX2
Use KTX2 when…
- glTF 3D Models (KHR_texture_basisu)
- WebGPU and WebGL Applications
- Game Engines (Unity, Unreal, Godot)
- Augmented and Virtual Reality (AR/VR)
Nikon-NEF
Use Nikon-NEF when…
- Professional Digital Photography
- Non-destructive Image Post-Processing
- High Dynamic Range (HDR) Imaging Archival