according to this article epson release information from Wilhelm to demonstrate the new yellow dye has substantially improved longevity, although I didn't see or here this at the booth myself. I assume they wouldn't be bringing it up if they didn't feel it wasn't so.
Although the >200 year estimates being reported in the cited trade show article do indeed suggest improved light fade resistance for the new UCHD
pigment ink set compared to the current Epson K3VM or HDR pigment sets, it's hard to read much more into the results than that because the WIR endpoints are based on densitometric measurements with liberal amounts of change allowed at the testing endpoint (e.g. 35% pure yellow loss, 12-18 % color balance shifts, etc). Also, percent density losses are not visually linear nor does WIR publish the actual fading curves, hence it's impossible to say what the aged image appearance may look like in 25, 50, or 100 years let alone over 200 years. The progression of visual appearance change in the artwork over the course of time is the key to what should be of interest to serious printmakers and to the retention of the artist's original intent, not the fact that a print is claimed to last a century or more. Even lignin-filled acidic newsprint will easily last that long if one tolerates liberal amounts of media discoloration and paper embrittlement over time. In other words, any print made today on just about any media may still have some functional (i.e.,historic, artistic, or sentimental) value a century from now, but it won't necessarily have retained a pleasing appearance, and disconcerting changes may be unavoidable much sooner along the arch of time.
Another interesting fact is that a 200 year Wilhelm Display rating requires 400 megalux hours of light exposure. Even with very intense light fade testing units, it would take several months or more to rack up that level of exposure, indeed well over a year if more reasonable accelerated aging conditions are used to accumulate this dosage or come close enough so that further extrapolation to the anticipated endpoints can be made. Thus, we can conclude that the WIR testing of the P600 printer and inks was performed under contract to Epson and is based on samples made on prototype equipment and pre-production inks in order for any test results to be ready in time for product launch.
Unlike other testing labs, AaI&A only tests commercially available systems that anyone can buy. The P600 has only just recently reached store shelves in the US, so it's going to be a while before I will have any substantive test results to share with the printmaking community. That said, I am eager to get started because I do anticipate we will see improved performance, especially on media that have stable media white points. BTW, neither Epson Exhibition Fiber paper nor Epson Premium luster cited in the article as attaining 200+ year ratings have stable enough media white point properties to ever be rated that well by AaI&A, no matter how lightfast the UCHD inks turn out to be. It takes both very stable media and very stable inks and also excellent compatibility between both in order to truly deserve such breathtaking "years on display" ratings.
cheers,
Mark
http://www.aardenburg-imaging.com