Overview - ISO 2846-1:2017 (printing ink sets, four-colour printing)
ISO 2846-1:2017 defines the colour and transparency requirements for process ink sets used in four‑colour offset lithographic printing - specifically for sheet‑fed and heat‑set web (and related radiation‑curing) processes. The standard specifies the printing conditions (using a laboratory printability tester), a reference substrate (Annex A, C2846), measurement geometry and methods to verify conformance so that proof and production inks produce consistent colour results across sites.
Keywords: ISO 2846-1, printing ink sets, four-colour printing, offset lithography, colour and transparency, reference substrate.
Key topics and technical requirements
- Scope: Colour and transparency characteristics for each process ink (CMYK) intended for proof and production offset lithography. Fluorescent inks are excluded; pigments and detailed spectral recipes are not mandated.
- Reference substrate: A defined substrate (C2846) is used to ensure repeatable colorimetric comparisons (Annex A).
- Test prints and printing conditions: Test prints are produced at several ink film thicknesses according to ISO 2834‑1 to cover the intended film thickness range for the process.
- Colorimetric conformance: Measured spectrally (ISO 13655, measurement condition M1; 0°:45° or 45°:0° geometry) and compared to reference colour values. Conformance is assessed by ΔEab values across film thicknesses - a sample is conformant if at least one printed thickness meets the ΔE tolerance.
- Transparency evaluation: Determined by printing chromatic inks over a black substrate and computing a transparency value (T) from the slope of ΔE* vs ink film thickness regression. A minimum reciprocal-slope (or negative slope condition) is specified.
- Drying and measurement: Samples must be fully dried (oxidative, heat‑set or radiation curing as appropriate) before spectral measurement. Measurements use CIE observer and D50 illuminant with calibrated UV level.
Applications and who uses it
- Ink manufacturers - to formulate and certify process inks that meet industry colour and transparency benchmarks.
- Commercial printers and prepress/press operators - for process control in sheet‑fed and heat‑set web offset production and proofing.
- Proofing houses and color labs - to verify that proof inks and production inks will yield consistent results.
- Quality assurance and procurement teams - to specify inks and substrates that meet reproducible colour standards.
Practical value: ISO 2846‑1 enables predictable colour reproduction across suppliers and print sites, simplifies colour separations, and supports compliance with wider print production standards.
Related standards
- ISO 13655 - Spectral measurement and colorimetric computation (measurement M1)
- ISO 2834-1 - Laboratory preparation of test prints (paste inks)
- ISO 12647-2 - Process control for offset lithographic printing (related colour specifications)
- ISO 8254‑1, ISO 535, ISO 536 - referenced test methods for substrate and gloss/absorbency characterization
For manufacturers and printers aiming for consistent CMYK output in offset lithography, ISO 2846‑1 is a core reference for ink colour and transparency verification.