I considered sun fade, but I don't think so. The lack of color is even, and only in the yellow spectrum. Fading would likely have claimed the red first, then faded the other colors. The yellow is clearly missing from every part of the inlay and the intensity of each color varies from strong to weak; some colors are clearly not faded at all. Look at the N, V, A, L, and B. None of this have the softenig effect of fading. They are sharp and high contrast, they are just off. If you understand color theory, you can see they all appear to be missing the yellow ink in the 4-color process (except the black A, of course).