Optical brightening agents (OBAs) are widely used in the printing industry to alter the appearance of papers and other printing medias. The bluish fluorescence of OBAs has caused color management problems since the early days. There are various remedies, but OBAs remain an unpredictable nuisance to color management practitioners.
The technology for measuring fluorescent samples has existed for a long time. But the equipment required is too big, too expensive and too slow to be practical for color management work.
In 2009, the ISO standards for color measurement and viewing were updated to more clearly specify the illumination. These changes were intended to solve the OBA problem for D50 illumination, which is the standard in graphic arts and color management. This spurred the development of new measuring instruments that unexpectedly provide the information needed to solve the general problem of color management with OBAs.
This paper explains some techniques we developed to utilize this information. By measuring the relative UV excitation of the viewing environment, it is fairly simple to compute correct colorimetry for any illuminant. This work suggests possible improvements to standard data sets. We also make recommendations for future updates of the ISO standards.