Aardenburg lightfastness tests available.

[Kirk Gittings]

The Aardenburg paper/ink ten year light fastness tests are available now:

http://www.aardenburg-imaging.com/digitalprintresearch.html

of note is the difference between Canon/Epson OEM inks and MIS third part inks.

[Oren Grad]

Thanks for posting Kirk, I wasn't aware of these.

[Peter De Smidt]

Yep, thanks Kirk.

[David Luttmann]

Thanks a bunch!

[Greg Lockrey]

These are very useful, thanks.

[Kirk Gittings]

The new Aardenburg approach to light fast testing has been released. It requires a bit of reading to understand the numbers. As I read them the numbers are significantly lower than Wilhelms. Mark describes his new system as:

"the Conservation Display rating concept are my "treatise tacked to the cathedral door" regarding the lightfastness of modern digital print media. Whether the industry will embrace the concepts remains to be seen......."

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

[MHMG]

Kirk invited me to make a comment in this thread. Not previously a member, I am thus new here ...will have to dust off my Linhof and get some Large format photography going again.

The new AaI&A conservation display ratings are designed to track the very early stages of print deterioration where the prints still appear to be in overall excellent condition, but small yet measurable changes have taken place. The conservation display ratings are therefore "tougher" than the current industry-sponsored longevity ratings which attempt to predict later stages of deterioration where easily noticeable, often objectionable changes have occurred. The conservation display ratings should appeal to curators, conservators, collectors, and printmakers who want to know more about how well their prints will last on display not just how long it takes to reach noticeably faded states.

The conservation display ratings are expressed as an exposure dose rather than extrapolated to "years on display". I have long felt that in an effort to "keep it simple" the industry grossly oversimplified the light fading issue in the minds of the consumer. Real world average print illumination levels vary by orders of magnitude. By giving my audience megalux-hour ratings, I am gently urging them to make their own translation to illumination conditions that are more appropriate to their own use. It's not hard to do. Just use the good 'ole reciprocity law where Exposure = Intensity (illumination measured in Lux units) x time. That said, there's a very easy rule of thumb if you elect to use WIR illumination assumptions or even Kodak illumination assumptions. To translate megalux-hours to WIR years on display divide megalux-hours by 2. To calculate Kodak years on display, multiply by two.

So, for example, a print with conservation display rating of 10-20 meglux-hours can withstand 5-10 years on display by WIR standards, and 20-40 years on Display by Kodak standards. Both display time predictions are valid extrapolations to real world conditions, but which condition better matches your own print display environment? And again, the conservation display rated prediction is for prints still remaining in excellent condition, not easily seen as faded.

The fact that the Conservation Display ratings express a range rather than a single value, takes a bit more explanation. I have posted some papers on my website that discuss the I* metric (my colorimetric color and tonal accuracy algorithm published in 2004) and the concepts behind both the I* metric and the new conservation display ratings. Not the easiest bed time reading I admit, but the papers were aimed primarily at my scientific colleagues even though I've attempted as best I can to make the work accessible to everyone.

So what's with the conservation display rating's exposure range rather than just posting a single predicted value? Basically, an exposure range is needed to provide guidance on what exposure dose will fade the weakest colors in the system versus how much is required to fade all colors to a given overall average response. Selective versus global color fading patterns are a rather new attribute of modern digital print media. Traditional silver halide color prints tended to fade rather uniformly meaning pretty much all colors were fading with about the same amount of exposure. If you tracked a few colors in test you could pretty much infer what the overall systems response was going to be. In stark contrast, today we have systems where the weakest colors may be much weaker than the strongest colors. The quoted conservation display range figures reflect this new reality. Given two systems rated with the same lower limit of exposure, the system with the higher upper limit will enable more prints to appear in visually good overall condition longer (i.e., greater exposure doses). It's a statistical game of probability. Which colors do you have in your image and when will those colors form a faded arrangement of colors and tones that you will just begin to notice? Fading is image content dependent! More so with today's digital print media than ever. The Conservation Display ratings are designed to address these new paradigms.

I hope this explanation of the new work helps. It will probably take many more efforts on my part to get all of the science behind this new method into a more concise description for photographers and printmakers. In the meantime, I just hope the rated numbers begin to make their own "apples-to-apples" comparative sense of the light fastness of these fascinating new print processes.

[Kirk Gittings]

Sorry if I missed something in your website or the above. What about B&W ratings? Many of us are most interested in b&w prints. Wilhelm's rating always show a big difference between color and "B&W" prints. I know this is complex because with ink systems like K3 there is allot of color inks in even "neutral" monotone print. So unless one is using Cone inks, in effect all b&w images are really color images. Therefore is there any meaningful difference in testing a b&w color image vs. a regular color image? Also are you also going to test media like Fuji Crystal Archive?

[MHMG]

Crystal Archive is in test and is a public link. You can download the reports, and there is also a news article about it on my site:

http://www.aardenburg-imaging.com/news.50.html

Not yet rated but getting close. I will continue these materials well beyond rated endpoints just to let everyone see how they do along the pathway to greater deterioration. The new Fuji Drylab 400DL "drylab" prints are also in test (this equipment is now being phased in at Ritz Camera, Walmart, and other retailers) The 400DL test report has private links at this time.. sorry about that... enough said.

As for B&W testing, all that is required to get this going is for me to make a general-purpose B&W target. It is easy to make. The I* metric works just as well for color as for B&W (in fact if you think of B&W from a color scientist's point of view, B&W prints are just a unique kind of color print... good L* channel contrast, very low chroma, but defined hues). It is on my to do list with the intention to add it to the test target folder that members can download. I had hoped to have it done already, but man, I've been busy!

Thanks,
Mark

[Kirk Gittings]

I appreciate what you have been doing and I will be following your efforts closely. Keep up the good work! Competition in this field will be a great thing.

[MHMG]

I appreciate what you have been doing and I will be following your efforts closely. Keep up the good work! Competition in this field will be a great thing.

Well, I guess even my colleagues in the field of image permanence might also call it competition!

However, I tend to think of the new conservation display ratings as complementary to consumer-oriented display life ratings, supplementing them but not necessarily replacing them. In fact, In my mythical spare time, I'm working on a second fading criteria set that I have named the "Information Display" Rating. The concept will be to allow much more fading but constrained by the i* metric analysis of false color and tonal rendering so as to identify the point in the "life cycle" where a print is still relatively easy to restore via copying and digital enhancement. The desire by many consumers to take old family snapshots that are faded and often in bad physical condition and have new prints made occurs all the time. Hence there is a compelling reason to predict an endpoint in the fading curve where the chance to recover information content at a high level is still there. An "information display" rating would thus complement the Conservation Display rating. It's value would be great for many of the dye-based systems in use in the consumer segment of the market. They aren't nearly as robust as the pigmented prints and are often kept on display well past the point where they are very badly faded.

Thanks for your interest in my work. In this near depression economy, I know it is hard for people to support any discretionary activities these days, but I really do need new members to keep those new test samples entering testing and the research moving forward!

Best regard to all,

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

[Peter De Smidt]

I agree with Kirk. Thanks Mark!

[Nathan Potter]

This is nice work and the exposure dose concept is well allied to basic physical principles so can be utilized for specific on-site conditions. One thing not discussed is the effect of the bandwidth of exposing illumination particularly the effect of higher energy UV light on the ink materials and the paper type. I'm out of my field here but I'm presuming that with color inks some of the dyes or pigments contain materials which have a low enough bandgap to be substantially effected by higher energy UV through absorption of UV quanta. I'm guessing that such a phenomena is the basic solid state transition which results in fading.

At some point it might be useful to characterize wavelength dependent effects on color and paper. Again I'm assuming that the color materials would have discrete bandwidths rather than smeared ones so there could be dramatic differences in longevity between short and long wavelength illumination.

Hell of a lot of work though; and initial results are greatly appreciated.

Nate Potter, Austin TX.

[MHMG]

... One thing not discussed is the effect of the bandwidth of exposing illumination particularly the effect of higher energy UV light on the ink materials and the paper type. I'm out of my field here but I'm presuming that with color inks some of the dyes or pigments contain materials which have a low enough bandgap to be substantially effected by higher energy UV through absorption of UV quanta. I'm guessing that such a phenomena is the basic solid state transition which results in fading.

At some point it might be useful to characterize wavelength dependent effects on color and paper. Again I'm assuming that the color materials would have discrete bandwidths rather than smeared ones so there could be dramatic differences in longevity between short and long wavelength illumination.

Hell of a lot of work though; and initial results are greatly appreciated.

Nate Potter, Austin TX.

Nate, you are absolutely correct. The UV component in the incident illumination is a very important variable, so much so that many people mistakenly believe that the UV exposure accounts for nearly all of the fading in textiles, dyes, paints, etc. However, fading induced by visible energy, especially the blue end of the spectrum also causes significant fading. The ratio of UV to visible light in the incident illumination is thus an important test variable. Some systems are much more affected by the UV content than others (e.g. some use additives and coatings to "pre-filter" the UV so to speak, even when one isn't using UV protective glazing over a framed print.

The nature of the fade pattern can also change as you noted under varying spectra, and the I* metric can easily track the results very nicely. But one does have to set up the tests with the spectrum one is interested in studying. It's not as simple as it sounds. Do we test for worst case unfiltered sunlight, sunlight filtered by glass, acrylic, UV-blocking glazing like Polycarbonate or OP3 acrylic, etc? All of these spectral variations affect results, and all are encountered frequently in the real world not to mention tungsten, cool and softwhite Fluorescent, etc.,

The AaI&A light fade database has been designed to be extensible. I can add different samples tested using different illuminants, but at the moment my "standard" test conditions use a 5000K High CRI flourescent lamp plus common picture frame glass which, when all is said and done, closely simulates the UV/VIS ratio of natural daylight but daylight as if filtered by standard acrylic glazing. This condition filters some of the UV but leaves enough in the spectrum to activate optical brighteners (and fade them). OP3 plexiglass is also easy to implement (98% UV blocking), but this important "museum lighting" condition also shuts down optical brightener activity, so it poses a bit of a dilemma with today's modern OBA enhanced papers. If a printmaker deliberately chooses a bright white paper, should curators display the print in a way that detracts from the bright white look by de-activating the UV fluorescence of the paper under UV blocking glazing? My opinion is probably not, and thus I chose to standardize on a condition that keeps some UV in the mix (but not as much as worst case direct sun conditions).

Choices, choices!

[Nathan Potter]

Mark, great thanks for more clarification of your thoughts.

Nate Potter, Austin TX.