Free webp to jpg
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Image MIME Reference
Harlequin-PGB

Global Graphics Page Graphics Buffer

image/vnd.globalgraphics.pgb
VS

Khronos Texture

image/ktx
KTX

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

Equal browser support

Feature Support

Feature Harlequin-PGB KTX
Transparency (Alpha) ✕ No Yes
Animation Support ✕ No ✕ No
Progressive Loading ✕ No ✕ No
HDR Support ✕ No Yes
EXIF Metadata ✕ No ✕ No
ICC Color Profile Yes ✕ No
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 →
Khronos Texture
image/ktx
Extension
.ktx
Container KTX (Khronos Texture 1.1)
Compression Uncompressed / GPU Compressed (ASTC, ETC, BCn, PVRTC)
Algorithm
ASTCETC1 / ETC2BCn (DXT)PVRTCBasis Universal (in KTX2)
Color Depth 8-bit, 16-bit, 32-bit (Integer/Float)
Developed by Khronos Group
Released 2010
Magic Bytes
AB 4B 54 58 20 31 31 BB 0D 0A 1A 0A
Full KTX reference →

Browser Support Comparison

Browser Harlequin-PGB KTX
Chrome Chrome
✕ ✕
Firefox Firefox
✕ ✕
Safari Safari
✕ ✕
Edge Edge
✕ ✕
IE 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
KTX

KTX Strengths

  • Enables direct-to-GPU texture uploading, drastically reducing load times and CPU overhead in 3D applications
  • Supports complex texture types natively (mipmaps, cubemaps, 3D volumes, texture arrays)
  • Standardized across major Khronos APIs (OpenGL, Vulkan, WebGL) unlike vendor-specific formats like DDS
Limitations
  • Requires custom JavaScript loaders to parse and display on the web
  • Zero native support in consumer image viewers or 2D photo editing software
  • Format fragmentation: a KTX file containing an ASTC payload will fail to render on hardware that only supports BCn compression (KTX2 and Basis Universal solve this)

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
KTX
Use KTX when…
  • Real-time 3D Graphics
  • WebGL / WebGPU Applications
  • Mobile Games
  • Virtual/Augmented Reality (VR/AR)

More comparisons

Harlequin-PGB vs ACES → KTX vs ACES → Harlequin-PGB vs APNG → KTX vs APNG → Harlequin-PGB vs AVCI → KTX vs AVCI → Harlequin-PGB vs AVCS → KTX vs AVCS → Harlequin-PGB vs AVIF → KTX vs AVIF → All comparisons →
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