Orange and red ceramic tiles that are widely used as measurement standards for reflectance factor unexpectedly exhibit near infrared fluorescence. Two measurement methods, illuminating the sample with broadband light and spectrally resolving the reflectance or illuminating the sample with monochromatic light and using a broadband detector, are commonly used to measure reflectance factor. The effect this fluorescence component has on the measured reflectance factor utilizing different measurement methods is analyzed. (dagger)Published 2010 Wiley Periodicals, Inc. Col Res Appl, 36, 96-100, 2011; Published online 17 June 2010 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/col.20614