Metamer mismatching refers to the fact that two objects reflecting light causing identical colour signals (i.e., cone response or XYZ) under one illunimation may reflect light causing non-identical colour signals under a second illumination_ As a consequence of metamer mismatching, two objects appearing the same under one illuminant can be expected to appear different under the second illunimant. To investigate the potential extent of metamer mismatching, we calculated the metamer mismatching effect for 20 Munsell papers and 8 pairs of illunimants (Logvinenko & Tokunaga, 20 11) using the recent method (Logvinenko, Funt, & Godau, 2012) of computing the exact metan2er mismatch volume boundary. The results show that metamer mismatching is very significant for some lights. In fact, metamer mismatching was found to be so significant that it can lead to the prediction of some paradoxical phenomena, such as the possibility of 20 objects having the same colour under a neutral ("white") light dispersing into a whole hue circle of colours under a red light, and vice versa
