Remember the semi-controversial "window" study by Edwin Iracki of
Dupont Fluoroproducts, which said Epson Ultrachrome pigment ink
showed 20% yellow fading in two years, and near 100% in 7.5 years?
We discussed it in November 2006.

Yet another study (from last winter) shows that UV causes fading
of "professional giclee" pigment inkjet prints:
http://www.goldenpaints.com/justpaint/jp14article2.php

Summary: under a Q-Lab UV-A 351 bulb, (Epson?) pigment inks on
watercolor paper faded at about half the rate of dye-based inks
on glossy photo paper, which is to say REALLY FAST. Magenta
faded most quickly, followed by yellow, then cyan, then black.
After 400 hours, all colors faded about half as fast as dye ink.
After 1200 hours, magenta had changed 60 (Delta E) versus 92
for dye ink, more than half, and yellow had changed 40 versus 54,
much more than half. EOS.

The relatively superior performance of pigment inks could be
entirely attributable to the paper, rather than ink longevity.
Dye-based inkjet prints on matte paper last at least twice as long
as dye-based inkjet prints on glossy photo paper.