Overview
ISO 23498:2022 - "Graphic technology - Visual opacity of printed white ink" specifies a standardized method to measure the visual opacity of printed opaque white ink. It applies to white ink printed on transparent films and on white or coloured opaque substrates. The standard defines specimen preparation, measurement conditions and a visual-opacity metric designed to align with human perception (0 = fully transparent to 100 = fully opaque), and is intended for repeatable, comparable opacity results across printing workflows.
Key topics
- Scope and limitations
- Covers opaque white inks (neutral colourant, reflectance factor > 80 %) printed as produced (opacity of the printed result, not ink alone).
- Intended for transparent substrates or opaque substrates with CIELAB L* ≥ ~92 (Y = 80 ± 2) and C* ≤ 20.
- Specimen preparation
- Test chart comprises four regions: unprinted substrate (S), ink on substrate (IS), black printed region (B) and ink on black region (IB).
- Minimum print areas: typically 4 cm × 2 cm (transparent substrates) or 2 cm × 2 cm for some test patterns; half of the white region should overlap the black region for opacity comparison.
- Options for using a standard test substrate or production substrate (useful for inkjet and special materials).
- Measurement requirements
- Spectral/CIE XYZ measurements per ISO 13655 using 45°:0° (or 0°:45°) geometry and CIE Illuminant D50; measurement condition M1 is preferred (M0/M2 allowed if reported).
- Black region requirement: CIE Y ≤ 5 (CIELAB L* ≈ 27.7).
- Opacity metric
- Uses a visual-opacity metric (0–100) developed for perceptual agreement and consistent with the PDF “solidity” model; explicitly excludes using contrast-ratio alone.
- Metric is extendable toward coloured inks/substrates (Annex A) and draws on functions used in Spot Colour Tone Value (SCTV, ISO 20654).
- Standard maintenance
- Second edition (2022) supersedes the 2020 edition; editorial/technical corrections made.
Applications
- Quality control and specification of white-print opacity in packaging, labels, signage and point-of-sale graphics.
- Comparing printing systems or ink formulations (including digital inkjet) where printed opacity affects appearance.
- Ensuring repeatable production results for reverse printing on transparent films and multi-layer print workflows.
- Reporting and communication of opacity values between ink manufacturers, print service providers and brand owners.
Who uses it
- Print technologists, ink formulators and manufacturers
- Color QC and prepress professionals
- Packaging designers and specification engineers
- Digital/industrial inkjet developers
Related standards
- ISO 13655 - Spectral measurement and colorimetric computation (normative reference)
- ISO 2846-1 - Reference substrates (test substrate guidance)
- ISO 20654 - Spot Colour Tone Value (SCTV)
- ISO 3664 - Viewing conditions
- ISO 6504-3 - Opacity test charts
Keywords: ISO 23498:2022, visual opacity, white ink opacity, opacity measurement, graphic technology, transparent substrates, ISO 13655, printing quality control.