Bill, and everyone,

Sorry I didn't respond sooner. It's been a busy week. Your write-up on image permanence is very well reasoned, and a very nice statement that let's your clients know you take print permanence seriously. Your website and your work is really great, too!

The only factual correction I would suggest in the document is with this statement:

"The inks I use, Hewlett Packard’s Vivera pigment inks, have a life exceeding 275 years and black and white Vivera prints exceed 300 years. This is the time until just noticeable fading or yellowing occurs, so the image will, in fact, last much longer if some fading is tolerated."

The Wilhelm display ratings are actually based on a consumer-toleranced testing criterion for "easily noticeable" fade. For "just noticeable" fade the tests would have reached an endpoint sooner.

In contrast, the AaI&A Conservation Display ratings (CDR) are based on a criterion for "little or no noticeable fade" rather than "easily noticeable fade", hence are specified with the fine art printmaking community in mind where buyers/collectors will become concerned once they begin to notice even a small amount of fade or discoloration. Thus, AaI&A provides a a rating for early stage deterioration whereas Wilhelm rates the product performance at a later stage of more advanced deterioration. Neither scoring approach tells you the whole fading story. Due to non linearity of fade in many systems, one actually needs to look at the full fading curve response (posted at 10 megalux hour intervals in each AaI&A test report) in order to know the whole story.

That said, you can take the AaI&A megalux hour CDR scores and divide by 2 in order to put the AaI&A conservation display ratings on the same time scale as the WIR tests. For example, AaI&A gives the HpZ3100/OEM ink/HP Hahnemuhle Smooth Fine Art combination a CDR score of 67-114 megalux hours when displayed using standard acrylic glazing (note that standard acrylic eliminates more UV energy than ordinary glass but not as completely as UV blocking acrylic). On the Wilhelm predicted time scale at the WIR specified average light level of 450 lux for 12 hours per day the AaI&A CDR score yields a range of 33.5 to 57 years to retain excellent quality (i.e., "little or no noticeable fade") . Wilhelm rated this same printer/ink/paper combination at greater than 250 years, but again, that's the time predicted to reach "easily noticeable fade" when displayed under ordinary glass. For the serious collector, the sensible answer to keep the print from showing any fade over a longer time span than 33.5-57 years as predicted by the AaI&A test is simply to drop the average light levels on the print down to typical museum levels like 50 or 100 lux. Or, if you want to see the print under brighter and more pleasing light levels, say the 450 lux level used by WIR to make it's predictions but want it to remain in excellent condition for over a century, just don't illuminate it at 450 lux for 12 hours each and every day for the next 250 years!

Some forum readers here may wonder why AaI&A Conservation Display ratings express a range and not a single value score like other testing laboratories. It's because the viewer's ability to observe color and tonal changes in the print is image-content dependent. Some images will reveal the color and tonal weakness of the system more quickly than others because their specific color and tone content contains larger more obvious areas of the system's weakest performing colors. Processes where the all the colors tend to fade at similar rates will have a very narrow range expressed in the rating, whereas prints that fade selectively in a few colors much faster than most of the other colors can have a very large range.

On a final note, Bill, I also noticed you have a Z3200 in addition to a Z3100, and that you are a member of AaI&A. The AaI&A database is sadly lacking any tests with the Z3200 which has a different red ink than the Z3100. Can I gently urge you to submit some test samples?