Free webp to jpg
Image MIME Reference
ACES

ACES Image Container File

image/aces
VS

Global Graphics Page Graphics Buffer

image/vnd.globalgraphics.pgb
Harlequin-PGB

A complete technical comparison of ACES Image Container File and Global Graphics Page Graphics Buffer — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

Equal browser support

Feature Support

Feature ACES Harlequin-PGB
Transparency (Alpha) Yes ✕ No
Animation Support ✕ No ✕ No
Progressive Loading ✕ No ✕ No
HDR Support Yes ✕ No
EXIF Metadata ✕ No ✕ No
ICC Color Profile ✕ No Yes
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
Full ACES reference →
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)
Full Harlequin-PGB reference →

Browser Support Comparison

Browser ACES Harlequin-PGB
Chrome Chrome
Firefox Firefox
Safari Safari
Edge Edge
IE IE (Legacy)
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
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

When to choose which format

ACES
Use ACES when…
  • Visual Effects (VFX)
  • Digital Intermediate (DI)
  • Color Grading
  • Archival
Harlequin-PGB
Use Harlequin-PGB when…
  • Commercial Printing Output
  • Computer-to-Plate (CTP) Manufacturing
  • Prepress Soft Proofing (e.g., FirstPROOF)
  • Harlequin RIP Spooling Pipelines
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