Digital BW, The Print

Paul:
Yes, interesting results regarding the polyurethane--was that the solvent based, or water based product? Of course we all know that urethane does allow moisture migration. :-)

Regarding "Fade-O-Meter" (Atlas machine) and accelerated testing. Yes, these machines do provide all sorts of new variables to consider. I once ran some samples through a machine they have at the University of Nebraska. Decided that using that device requires lots of data history to be useful. I'll leave that to the likes of Henry and Mark.

And, regarding humidity, That seemed to be a major factor when considering dyes with their complex inter-reactions--much more so than pigments.  

An ideal inkjet receptor would be one of the swellable polymer base, that swells on initial contact with water, and then remains water impervious after that, providing protection against airborne contaminants.

John Nollendorfs 

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Paul" <roark.paul@...> wrote:
SNIP
> A fade test result of mine relating to coatings that I found interesting was that in a high humidity test a matte paper that was coated with the polyurethane faded faster than one that was not coated.  I speculate that the water vapor got in through the back and stopped the pigments from being dried out by the lamp.  Whether this would happen in normal display is debatable.  Accelerated testing is often said to exaggerate the longevity of the images because the brighter than normal light dries the pigments, and water/humidity acts as a catalyst for the fading/oxidation.  But, unless the print is encapsulated from both the front and back (perhaps by barrier paper), coatings that are just on one side of the imaging substance might actually have a negative effect.