Image MIME Reference
PSD
Adobe Photoshop Document
image/vnd.adobe.photoshop
VS
Sigma X3F RAW Image
image/x-sigma-x3f
Sigma-X3F
A complete technical comparison of Adobe Photoshop Document 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 | PSD | Sigma-X3F |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | Yes | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | Yes |
| EXIF Metadata | Yes | Yes |
| ICC Color Profile | Yes | Yes |
Adobe Photoshop Document
image/vnd.adobe.photoshop
Extension
.psd.psb.pdd
Container
Adobe Photoshop Document (PSD/PSB)
Compression
Uncompressed / RLE (Run-Length Encoding) / ZIP
Algorithm
RLEZIP (with or without prediction)None
Color Depth
1-bit (Bitmap), 8-bit, 16-bit, 32-bit (Float/HDR)
Developed by
Adobe Systems
Released
1990
Magic Bytes
38 42 50 53
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 | PSD | Sigma-X3F |
|---|---|---|
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✕ | ✕ |
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✕ | ✕ |
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✕ | ✕ |
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✕ | ✕ |
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✕ | ✕ |
PSD
PSD Strengths
- The undisputed global standard for layered raster graphics and non-destructive image editing
- Supports incredibly complex compositions combining raster data, vector shapes, live text, and adjustment layers
- Full support for advanced color spaces (CMYK, Lab, multi-channel) and 32-bit floating-point HDR workflows
Limitations
- Proprietary format: while the specification is published, complete feature-parity is rarely achieved by third-party software (e.g., smart objects and complex layer styles often break)
- Files can reach enormous sizes (gigabytes) due to the preservation of unflattened, high-resolution layer data
- Zero support for native rendering in web browsers or standard mobile 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
PSD
Use PSD when…
- Professional Photo Retouching
- Digital Painting and Illustration
- UI/UX Design Workflows
- Graphic Design and Print Production
Sigma-X3F
Use Sigma-X3F when…
- Professional Digital Photography
- Sigma / Foveon High-Acuity Imaging
- Non-destructive RAW Post-Processing