Overview
ISO/TS 21328:2022 provides guidelines and a practical procedure to generate multicolour print characterization datasets for CMYK plus Orange, Green and Violet (CMYKOGV). The Technical Specification covers pigment recommendations, target design and measurement practices to expand the printable colour gamut (expanded/extended gamut printing). The procedure is also applicable to CMYK combined with any subset of O, G or V and supports creation of colour-managed workflows (for example ICC n‑colour profiles) using spectral and colorimetric data.
Key topics and technical requirements
- Multicolour characterization procedure: Stepwise guidance to produce and combine spectral datasets (e.g., CMYK subsets and complementary substituted ink runs) to form a master CMYKOGV dataset. Custom seven‑colour targets or adapted IT8 targets are referenced.
- Pigment selection: Recommendations for OGV pigment choices to optimise gamut. Historical studies (e.g., C.I. pigments Orange‑16 and Orange‑64) are cited as examples - availability or suitability may vary by process.
- Measurement and colour computation: Measurement must follow ISO 13655; use appropriate instrument modes (M1 recommended when OBAs and UV viewing expected; M2 when UV‑free viewing is expected). Tonal value and halftone metrics use ISO 20654 or CMYK TVI methods as applicable.
- Viewing and verification: Visual assessment under ISO 3664 viewing conditions; device setup, printing verification and reporting steps to confirm fit to aims and reproducibility.
- Data formats and colour exchange: Use of spectral and colorimetric reporting formats (e.g., CxF/X per ISO 17972‑1) to enable accurate colour communication and metadata transfer for profiling and process control.
- Scope limitations: Recommended pigment sets may not suit all print or digital processes; the document emphasises process‑specific validation and substrate considerations.
Practical applications
- Expanding colour gamut for packaging, commercial and high‑fidelity image printing.
- Developing ICC n‑colour profiles and colour managed workflows for multicolour presses.
- Selecting additional process inks (OGV) to meet brand or spot‑colour objectives while maintaining consistent reproduction across print runs.
- Standardising measurement, reporting and verification for suppliers, converters and brand owners to ensure predictable colour reproduction.
Who should use this standard
- Print service providers and press operators implementing multicolour/expanded gamut printing
- Packaging designers and brand colour managers needing consistent colour reproduction
- Colour scientists, prepress technicians and workflow integrators creating ICC n‑colour profiles
- Ink and substrate manufacturers evaluating pigment performance for multicolour processes
Related standards
- ISO 3664 (viewing conditions)
- ISO 13655 (spectral measurement and colour computation)
- ISO 17972‑1 (CxF/X colour data exchange)
- ISO 20654 (spot colour tone value)
- ISO/PAS 15339‑1 (substrate corrections and Characterized Reference Printing Conditions)
Keywords: ISO/TS 21328, CMYKOGV, multicolour print characterization, expanded gamut printing, colour gamut, pigment selection, ICC n‑colour profile, spectral measurement.