Whiteness is a measure of light reflectance across all wavelengths of the visible spectrum. It is commonly measured through the CIE Whiteness Index, developed by the France-based International Commission on Illumination. This index refers to measurements made under D65 illumination (standard outdoor daylight). Perfect natural whiteness would be CIE 100, but it is possible to reach higher CIE values by adding fluorescent agents such as Optical Brightening Agents (OBA). This is why Navigator has a whiteness of 169 CIE. The higher the value, the whiter the paper.
“THIS INDEX REFERS TO MEASUREMENTS MADE UNDER D65 ILLUMINATION…”