On Aug 13, 1:59 pm, tomm42 wrote:
On Aug 11, 7:02 pm, 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.

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

UV causes most things to degrade. It isn't too good for paper either.

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.

This makes sense, watercolor paints will do the same, this is why
there are display standards. I have been inkjet printing commercially
since 2000. If your inkset is not covered by Wilhelm, ie a 3rd party
ink, a south window test is your best ACCELERATED test. Depending on
who you believe and how much bright south light I have heard 1 day = 1
year to 1 week = 1year, under standarized viewing conditions. View the
Wilhelm site to get what he feels are standardized conditions.

If you want to do accelerated testing on the cheap for peace of mind,
then putting the print under cheap acrylic sheet plexiglass (Perspex,
Lucite) made without a UV blocker is about as aggressive a test as you
can get. Water lear is quite a bit more transparent than glass and
allows a lot more UV through. Colour A3 posters from my Canon i9000
are visibly faded after about 4 weeks on a south facing UK wall. The S
facing village notice board has a Perspex cover.

http://www.allplastics.com.au/03/fil...ingPXTD236.pdf

Tranmission graph on p3. There is a more expensive VE grade with a
very good UV blocking property.

So all this guy is doing is accelerated testing so no surprise. Stick
a photo from a chemical printed source their and watch what happens.

Cibachrome lasts surprisingly well under these conditions. But it is
not imortal.

Regards,
Martin Brown