Somehow I don't think you are going to beat the OEM makers for longevity with a 3rd party ink. One of the two longevity testers on here may know better. I see Mark above has already responded.
I do know my 3rd party inks do not hold up well in bright sunlight against the OEM maker's ink out in the back yard. I've had stuff fade in as little as 2 days outside on a pole, while the OEM beside it is still looking good after two months even with rain, sprinklers, sun, and 100+ F. heat beating on them both. I'd rather subject the prints to the worst possible scenario that placing them under a lamp inside and extrapolating the results to make a claim of lasting a week to 100-200 years. If it fades in a couple of days outside, that's telling enough for me if the OEM is still holding up well against a 3rd party ink.
Fwiw, I have a cheap portable printer in my arsenal called an Epson Charm. Makes 4x6 prints only. The thing turns out some really nice prints on location and I thought for a long time it was a pigment ink only to find out it was their Claria dye ink. I've left prints from it outdoors and indoors and they still look freshly printed. My third party inks have faded badly, even though I used the same glossy Epson paper in both printers (i.e. The Charm, and the 3880 with non-OEM.).
I suspect Epson, with their new HD ink being even blacker in the P-series than the inks in the 3880, has made the ink particles even finer and packed tighter to produce that higher D-max black. That should keep them from fading a bit better too. No doubt their newest formula is under a very tight licensing too that probably will be hard for the 3rd parties to come by.
Somewhere down the road I may suck out some P-series ink carts and feed it into one of the other 3880's and see how that experiment goes.
SG
