ISO 11475:2017

Overview

ISO 11475:2017 - "Paper and board - Determination of CIE whiteness, D65/10° (outdoor daylight)" specifies the standardized procedure for measuring the CIE whiteness of papers and boards as seen under the CIE D65/10° (outdoor daylight) illuminant. The method uses reflectance data across the full visible spectral range (VIS), and is designed for white papers and boards with or without fluorescent whitening agents (FWAs). It is not applicable to coloured papers containing fluorescent dyes.

Key topics and technical requirements

• Measurement principle: Calculation of the CIE whiteness value (W10) and tint values (green/red T_W10) from reflectance/spectral data and CIE tristimulus values for the 10° observer.
• Full VIS reflectance: Uses reflectance data over the full visible spectrum (contrast with ISO brightness, which uses the blue region only).
• UV adjustment for fluorescence: Specifies a method to adjust the UV content of the instrument illumination so whiteness values correspond to CIE D65. Results for fluorescent materials depend on UV content.
• Elimination of fluorescence: Describes use of a sharp cut-off UV‑absorbing filter (transmittance ≤ 5.0% at ≤ 410 nm and ≤ 50% at 420 nm) to measure reflectance with fluorescence emission removed.
• Apparatus and calibration:
  • Reflectometers or spectrophotometers meeting ISO 2469 geometric, spectral and photometric characteristics.
  • Use of non‑fluorescent and fluorescent reference standards (IR3 level) and working standards; UV calibration service described in Annex B.
  • Instruments must provide photometric linearity (e.g., up to 200% scale reading) in the fluorescent emission region.
• Calculation and reporting: Procedures for computing whiteness, fluorescence component (F10), tint, precision data and required test report elements are included.

Practical applications

• Quality control and acceptance testing in paper and board manufacturing to ensure consistent visual whiteness under outdoor daylight conditions.
• Product specification and supplier verification for stationery, packaging, coated papers and graphic papers where perceived whiteness matters.
• R&D and formulation work involving optical brightening agents (FWAs).
• Color management and matching for printers, packaging converters and brand owners concerned with daylight appearance.

Who should use this standard

• Paper and board manufacturers and converters
• Independent testing and calibration laboratories
• Instrument manufacturers (spectrophotometers/reflectometers)
• Quality assurance, procurement, and R&D teams in paper‑using industries
• Standards bodies and technical committees for optical measurement

Related standards

• ISO 2469 - Measurement of diffuse radiance (reflectance) factor (normative reference)
• ISO 11476 - CIE whiteness under indoor illumination (complementary)
• ISO 186 - Sampling to determine average quality
• CIE 15.3-2004 (CIE whiteness formula) and ASTM E308 referenced for tristimulus computations

Keywords: ISO 11475:2017, CIE whiteness, D65/10°, paper and board, fluorescent whitening agents, reflectance, spectrophotometer, UV adjustment, ISO 2469.