ISO 22028-1:2016

Overview

ISO 22028-1:2016 defines the architecture and requirements for extended-gamut colour encodings used in digital photography and graphic technology. The standard specifies what information is needed to unambiguously describe a colour encoding so images can be stored, edited and exchanged without loss of meaning. It covers pictorial images from original scenes as well as images containing text, line art, vector graphics and other artwork. ISO 22028-1 introduces a reference image-state-based digital imaging architecture to classify colour encodings (but does not mandate specific workflows).

Keywords: ISO 22028-1, extended colour encodings, extended-gamut, digital photography, graphic technology, image-state-based architecture, colour management.

Key Topics and Requirements

• Image-state model: Defines image states used to classify encodings, including scene-referred and picture-referred states (with subtypes such as original‑referred and output‑referred).
• Colour encoding requirements: Specifies mandatory information to define an encoding:
  • Colour space definition (colourimetric vs appearance vs device-dependent)
  • Digital encoding method (how numeric code values map to the colour space)
  • Set of valid colour values and permissible ranges
  • Image state associated with the encoding
  • Reference viewing environment and reference imaging medium
• Transforms and workflows: Defines roles for colour‑rendering transforms, colour re‑rendering transforms, and film rendering/unrendering within the architecture.
• Normative references and terminology: Builds on established colorimetry (e.g., ISO 11664 series) and provides standardized terms and definitions.
• Informative annexes: Include example workflows, characteristics of existing encodings, and criteria for selecting an encoding.

Note: The standard calls out potential patent considerations for certain clauses; users should verify patent/licensing status as needed.

Practical Applications and Who Uses It

ISO 22028-1 is intended for professionals and organizations who need reliable, interoperable colour encodings across capture, editing and output pipelines:

• Software developers of image-editing, DAM and colour-management tools
• Camera and scanner OEMs defining raw and intermediate image encodings
• Print and proofing houses and prepress engineers preserving extended gamuts
• Color scientists and imaging researchers designing new encodings or transforms
• Standards bodies and integrators ensuring consistent image exchange across systems

Benefits include improved interoperability, reduced ambiguity in colour data exchange, and support for workflows that preserve wide colour gamuts throughout digital image storage and manipulation.

Related Standards

• ISO 22028 (multi-part series) - other parts define example encodings:
  • Part 2: ROMM RGB (Reference Output Medium Metric RGB)
  • Part 3: RIMM RGB (Reference Input Medium Metric RGB)
  • Part 4: eciRGB (European Colour Initiative RGB)
• ICC colour management specifications (profile connection space) and ISO 11664 (Colorimetry) are complementary references.