ISO 13655:2017 is the core international standard for spectral measurement and colorimetric computation in graphic arts. It supports offset, flexographic, gravure, screen and digital printing workflows and gives suppliers and printers a common language for measurement. It does not replace the process standard, product tolerance or visual viewing specification.
What ISO 13655 covers
The standard defines procedures for measuring spectral reflectance, transmittance and emission where applicable, and for calculating graphic-arts colorimetric quantities. It addresses instrument properties, measurement conditions, backing and data treatment. A process document such as the relevant part of ISO 12647 then uses those measurement rules to define aims and control parameters.
The four measurement conditions
| Condition | Practical meaning |
|---|---|
| M0 | Legacy illuminant-A type condition without tightly defined UV content. Historical data may use it, but OBA papers can vary between instruments. |
| M1 | D50-aligned measurement intended to improve agreement for fluorescent papers and modern graphic-arts viewing conditions. |
| M2 | UV-suppressed condition that largely removes fluorescence and is useful when a UV-cut result is specified. |
| M3 | Polarized, UV-suppressed condition used in particular process-control applications, including reducing surface-reflection effects on wet ink. |
No condition is universally “best.” Use the one required by the printing condition and exchange it with the data. The same sample may legitimately produce different results under different M conditions.
Backing, geometry and aperture remain essential
A translucent print changes when placed over white versus black. ISO workflows therefore define backing conditions, and process standards state which one applies. The instrument’s 45°:0° or 0°:45° geometry, aperture and spectral sampling also affect comparability. Identify both the illuminated and measured areas when small control patches are used.
Colorimetric computation is part of the method
Spectral data are converted to XYZ, L*a*b* and color differences using a named illuminant, observer and calculation. D50/2° is common in print workflows, but the contract governs. Store spectra and metadata together so values are not detached from the method that created them.
Apply ISO 13655 in production
- Make the M condition explicit in targets, reports and supplier agreements.
- Use the required white or black backing and sample state.
- Verify instruments and evaluate inter-instrument agreement on real substrates.
- Align visual appraisal with ISO 3664:2025 viewing conditions.
- Use the applicable process standard to define aims and tolerances.
See How to Measure Printed Color, Optical Brighteners and UV and D50 vs D65 for the most common practical consequences.
Last reviewed 22/09/2026 · Level: Advanced
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