My Diamine Crimson was I think a fairly bright red when i bought it about 1.5 yrs ago. Normal room storage. Now it seems more of a brownish red. Same thing happened to my FPR Painted Desert- i feel it's become darker/browner over the past year, in the bottle.
Or maybe it's just my mind, maybe my brain has become more accustomed to looking at bright colorful inks, and the inks I 'thought' were bright back in the beginning really weren't bright to begin with?
Ok wait, maybe I can find some journal entries from back then and can compare them... (duh!)