Bill Tuthill wrote:
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.

Yes, I remember that.
IIRC exposure conditions were approximating full sun exposure in
Florida. The DuPont coating system (film) was intended for protecting
outdoor signs etc. Dupont makes some great products.
IMO, not too much point getting carried away with results for this when
you are concerned about longevity of photographs. No colour photographs
from any process would last in that environment. If you want to make
outdoor signs, get a solvent ink sign printer - don't use your photo
printer or costco prints.



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.

Printer and inkset not specified. Canon and HP also make pigment
inksets for photo printers. Third party ink makers also supply some
pigment inks.

Don't forget that these guys - "golden paints" - are trying to sell
expensive varnish to make prints last longer. Throwing a bit of FUD in
to the mix might help sales.


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.

Dye based inks on matte paper are a very bad idea for longevity. UV is
the least of problems to be expected.