Print Fading Question

[JSR]

I've just been looking over some of the PDFs at Wilhelm Research and I was left with a question regarding fading.

Most of my printing is colour glossies, so I'm mainly looking at Epson Premium Glossy Photo Paper and I'm comparing Ultrachrome Hi-Gloss (R1800) and Ultrachrome K3 (3800/R2400/etc).

According to Wilhelm's figures, the Ultrachrome Hi-Gloss inkset is capable of better fade resistance than K3, except if the print is displayed unframed ("Bare bulb").

If framed under glass, UHG resists fading for 104 years, for K3 it's down to 85 years.
If framed under UV filter, UHG is listed at >175 years, for K3 it's down to 98 years.
If left unframed (bare-bulb), UHG is 34 years, K3 is 60 years.

How is it that UHG is significantly better at resisting fading than K3 if framed (either glass or UV filter), but K3 is significantly better if left exposed to the elements. What's different about the two Ultrachrome inksets that accounts for this?

Any clues?

Regards,
JSR

[Alchemist]

JSR,

Wilhelm results are best used as a very rough yardstick and not to be taken as absolutes.

K3 inks reportedly have the individual pigment particles encapsulated in a resin similar to some older toners ( so it is not a valid patented process as claimed by many paid writers in photo mags). The solvent in the ink may evaporate more quickly in unprotected displays and do less damage to the gloss paper than the older pigmented ink. Without knowledge of the exact specimen handling/test proceedures this is just a wild quess.

ASTM is attempting to draft updated standard test proceedures for inkjet image permanence. When these ASTM and DIN practices are adheared to by the OEMs and independent labs then we can better understand published results. Today the exact proceedures for tests results ( so that results can be duplicated independently) are not usually provided. This was a rather lengthy subject, that we discussed at the resent World Expo forum on image permanence. Until resolved, search for independent results, and conduct your own testing ( unfortunately after purchase of the printer and ink system).

Regards,


Alchemist