Aardenburg archival test results....?

[Kirk Gittings]

I'm a little slow sometimes, but after reading their website material I am still pretty confused. In plain English how do you interpret the Aardenburg test results. What are the key test numbers to look at?

http://www.aardenburg-imaging.com/ac...gingtests.html

[MHMG]

Hi Kirk,

There is indeed a lot of information to digest on the AaI&A website. Perhaps it's best to simply start with the basics of light exposure. The AaI&A light fade test samples are measured for changes in color and tone at 10 megalux hour exposure intervals and the tests continue through early stages of fading well into high levels of fade. Fugitive print processes will fade noticeably in just a few megalux hours of exposure, while moderately lightfast systems may take 30 to 50 megalux hours and very stable systems will pass 100 megalux hours in test and still remain in excellent condition (little or no noticeable fade observed). The test target colors are measured and reported colorimetrically, and the target colors in the PDF are color managed and generated directly from the measurement data (i.e., not scanned, so the reproduction accuracy is as good as today's calibrated display monitors can show). So, if the colorimetric data is a bit overwhelming, then just look at the "before" and "after" target appearance in the reports and you will get a feel for how much fade is occurring as the tests progress.

Next, there's a table on page 4 in each test report that will help you convert megalux hours to "years of display" time. The reason Aardenburg doesn't do "predicted dispaly life" as standard procedure like other testing laboratories is that real world light levels vary so greatly. I concluded it's foolish and misleading to try to standardize on a single "average" light intensity where prints are routinely displayed when in fact even in the same home, the average light levels striking prints at various locations in the house can vary by two to three orders of magnitude. That said, one of the values in the table, 450 lux for 12 hours per day, is the value used by Wilhelm Imaging Research to make its predictions of display life. Thus, you can cross-reference Aardenburg exposure doses to WIR years using this table value.

Keep in mind that the commonly cited industry ratings are based on a different test target than AaI&A uses and on a very different criterion for judging "easily noticeable fade". If you'd like to get a feel for easily noticeable fade, check out the Fuji Crystal Archive II samples in the AaI&A database (these samples are free to the public). This product has been variously rated over the years as "lasting" 60 years on display and more recently 40 years on display (the rating changed primarily due to an additional set of lighter density color patches being added to the industry test method). At the industry extrapolated light level, 40 years requires 80 megalux hours of exposure, and 60 years requires 120 megalux hours. Take a look at those megalux hour values in the report and see for yourself what "easily noticeable fading" looks like when using the Aardenburg 30 color patch test target!

I'll stop there for now. There's much more info I can share, but it can wait!

cheers,

Mark
http://www.aardenburg-imaging.com

[Tyler Boley]

May I again take this opportunity to bug all interested in the longevity of the processes we use, and surely people committed to their work enough to use large format cameras should be, to subscribe and support Mark's work.
It's literally the only reliable and independent information we have on the care and survival of contemporary photographic art. Rates are reasonable, as they say.
Tyler

[Oren Grad]

What Tyler said. It's $25 a year, well worth it both to gain access to the full set of test results and to support this important work.

[Kirk Gittings]

FWIW I am a subscriber. I believe in what they are doing and appreciate being able to support their efforts.

[Photomagica]

For those who haven't checked the Aardenburg site, it is a rich resource for understanding the permanence of various ink sets on a wide variety of papers. Given the past issues of inkjet permanence I feel I owe it to myself as an artist and to my buyers to use ink and paper combinations supported by strong evidence for longevity. I appreciate that Mark McCormik-Goodhart provides me with the information needed so I can confidently select from a wider range of materials.
Bill Peters

[Kirk Gittings]

I get it now, an impressive source of info. I can't figure out though what PASS means in some of the columns?

[MHMG]

I get it now, an impressive source of info. I can't figure out though what PASS means in some of the columns?

I wrestled with what term to put there, and "PASS" is all I could come up with! By "PASS" I mean that neither the lower or upper limit of the conservation display rating has yet been reached. Testing must continue further. So, by checking the exposure level in the "status" column, you can tell without downloading the report that the passing sample's worst 10% of the color patch performance has not yet triggered the lower CDR limit at the exposure dose currently listed in the Status column of the database. Status thus tells you much exposure the test sample has received to date.

Once the lower limit is reached, then you will see CDR values like, for example, 23-40+ megalux hours. The first value in the range is the lower CDR value, and the plus sign means that the upper CDR limit hasn't yet been reached. Once both limits have been met you will see the final result in the CDR column, and the rating will have no more "+" sign in the reported range value. Sometimes, not often, systems will trigger both upper and lower limits simultaneously, and in rare instances the upper limit which represents the overall average response will trigger before the lower limit. In these situations, the Conservation rating will look like, for example, 37-37 megalux hours. Close or equal upper and lower limits in the rating are an indicator of a system that fades more uniformly over all of it's color and tonal range, whereas a rating with a wide CDR rating range indicates the system has a much larger distribution of fade between the weakest and strongest colors/tones in the image.

There is a document on the Aai&A website that explains the Conservation Display rating in more detail. It is called "An Overview of the AaI&A Conservation Display Ratings" and can be found on the documents page as well as by using a quick link located on at the top of the light fade database page.

[MHMG]

For those who haven't checked the Aardenburg site, it is a rich resource for understanding the permanence of various ink sets on a wide variety of papers. Given the past issues of inkjet permanence I feel I owe it to myself as an artist and to my buyers to use ink and paper combinations supported by strong evidence for longevity...
Bill Peters

Thank you Bill, Tyler, Oren, and Kirk for the kind words of support. Kirk could have emailed me directly with his question about interpreting the Aai&A test results, but I'm glad he opened the discussion up to all members of this forum. I'm happy to take some time over the next few days to keep contributing to this thread, a bit or two at a time.

So, keep the questions coming if you like. I'll do my best to explain.

kind regards,
Mark
http://www.aardenburg-imaging.com

[Photomagica]

For I wrote a short introduction to image permanence for non-experts on my blog:

http://www.photomagica.com/blog/?page_id=117

The reason for the blog entry is I do get questions from buyers and some come saddled with misinformation or dated or partial information. I've tried to make this piece as clear and accurate as possible while keeping it readable by non-enthusiasts. Comments welcome.
Bill