Yeah though some black ano lasts longer than others. I've seen some Art Stump ano parts from the 70s that are still nice and dark to this day. These '70s Universal 68 brakes were still fairly dark when I sold the bike ~10 years ago.



Maybe starting to look a little purple?

I'm guessing there are differences in the actual dye used, but also in the thickness of the ano and how it was sealed after the dye job. Just guessing though.

Red also seems especially prone to fading in sunlight. My blue Modolo Professional brakes from 1980 appear to be as rich and dark a blue 45 years later as on day one. I'm not normally a fan of color ano because it looks terrible when scratched or worn thru to the alu below, but I am fond of those Modolo brakes for sentimental reasons.