No two observers perceive color the same. To one observer, the colors of two objects might match perfectly; yet to another, those same two objects might not match depending on the spectral characteristics of the colors of the two objects, their illuminant, and each of the observer's spectral eye response. Here we create a large, representative group of such observers – said to be metameric - from data that characterizes the variability in these characteristics over the human population. Further, we show that the degree of mismatch between any metameric pair of objects might be large enough that the color naming of each object can be different for certain observers.
Mark D. Fairchild, Rodney L. Heckaman, "Metameric Observers: A Monte Carlo Approach" in Proc. IS&T 21st Color and Imaging Conf., 2013, pp 185 - 190, https://doi.org/10.2352/CIC.2013.21.1.art00033