Image MIME Reference
Harlequin-PGB
Global Graphics Page Graphics Buffer
image/vnd.globalgraphics.pgb
VS
Sony SR2 Raw Image
image/x-sony-sr2
Sony-SR2
A complete technical comparison of Global Graphics Page Graphics Buffer and Sony SR2 Raw Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | Harlequin-PGB | Sony-SR2 |
|---|---|---|
| Transparency (Alpha) | ✕ No | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | ✕ No | Yes |
| EXIF Metadata | ✕ No | Yes |
| ICC Color Profile | Yes | Yes |
Global Graphics Page Graphics Buffer
image/vnd.globalgraphics.pgb
Extension
.pgb
Container
Proprietary Harlequin Raster Container
Compression
Uncompressed / Run-Length Encoding (RLE)
Algorithm
Proprietary RLENone
Color Depth
1-bit (Monochrome Separations), 8-bit (Grayscale), 8-bit/10-bit (Contone), CMYK / N-Color Spot Channels
Developed by
Global Graphics Software (Hybrid Software Group)
Released
1990s
Magic Bytes
Unknown (Proprietary Harlequin Header)
Sony SR2 Raw Image
image/x-sony-sr2
Extension
.sr2
Container
TIFF-based (Proprietary)
Compression
Uncompressed / Sony Proprietary Lossless
Algorithm
NoneSony Proprietary Lossless
Color Depth
12-bit (Per Channel)
Developed by
Sony Corporation
Released
2005
Magic Bytes
49 49 2A 00
Browser Support Comparison
| Browser | Harlequin-PGB | Sony-SR2 |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
Harlequin-PGB
Harlequin-PGB Strengths
- Unlike generic 1-bit TIFFs, PGB files inherently encapsulate vital print-job metadata within their headers (e.g., job name, page number, separation colors, screening angles)
- Highly optimized for ultra-fast viewing and processing within professional printing workflows
Limitations
- Completely proprietary and closed-source, locking its usage strictly to Harlequin-powered RIP environments
- Zero support in standard desktop operating systems, web browsers, or consumer image editing software like Photoshop or GIMP
Sony-SR2
Sony-SR2 Strengths
- Retains raw, unprocessed sensor data from legacy cameras, allowing modern raw processors to extract vastly superior image quality than what was possible in 2005
- Utilizes a standard TIFF container structure, ensuring that community-maintained open-source decoding libraries (like LibRaw) can easily parse and maintain support for it indefinitely
Limitations
- Completely obsolete format that has not been utilized in a new camera release in over a decade
- MIME detection via magic bytes is unreliable due to TIFF header spoofing, requiring deeper EXIF inspection
- Cannot be natively viewed in web browsers or standard operating system image viewers without specialized decoders
When to choose which format
Harlequin-PGB
Use Harlequin-PGB when…
- Commercial Printing Output
- Computer-to-Plate (CTP) Manufacturing
- Prepress Soft Proofing (e.g., FirstPROOF)
- Harlequin RIP Spooling Pipelines
Sony-SR2
Use Sony-SR2 when…
- Legacy Sony Cyber-shot/Alpha Photography
- Non-destructive Image Post-Processing
- Raw Imaging Archival