http://www.dpreview.com/forums/post/53234430A week or two in the sun can typically yield about 1 megalux hour of total light exposure. All third
party dye sets I've tested in the past fail noticeably in the 1-3 megalux hours exposure range, so the
test results you posted are empirically consistent with AaI&A standardized light fastness testing of
other third party dye sets. At the 450 lux per 12 hours per day indoor lighting assumption often cited
in industry-sponsored test scores, 1 megalux hour exposure is about 6 months on display. However, if you
place a print in a more conservatively lit area inside a home, the light level might average only about
50 lux or less. Initial fade rates are proportional to light exposure. Hence, it's entirely predictable
and possible that some prints made with fugitive third party dyes can remain in good condition for
several years or more on display when the light levels are kept sufficiently low. However, place those
same prints in a more brightly lit area and the fade happens much faster, so we don't need to wait 20
years to obtain useful light fade test results, but it does help to run an instrumented test where both
the color changes and the light exposure doses are rigorously measured and reported.
The older Canon Chromalife 100 dye set was also in trouble at under 5 megalux hour exposure dose on
microporous media due to a very poor performing black dye which Canon has now replaced in the 100+ set.
Swellable polymer papers improved the lightfastness significantly, but have largely disappeared from the
market due to other problematic issues. Samples of the newer Pro-100 chroma life 100+ set printed on
Canon's newer microporous RC papers for this printer are now in test and have already passed the 10
megalux hours exposure mark with little or no noticeable fading. A big improvement over the older chroma
life 100 set and also any third party dyes I"m aware of.
