Interesting Canon comment on "dye" fade resistance

Started Oct 22, 2012 | Discussions thread
Mark McCormick
Contributing MemberPosts: 750
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Re: Interesting Canon comment on "dye" fade resistance
In reply to detectorman, Oct 23, 2012

detectorman wrote:

Mark,

Could not at least light-fading resistance be tested using the Arrhenius method using various light fluxes. Some amount of heating from sunlight may be involved also. And humidity also--we used to test integrated circuits at 90 degrees C and 90% relative humidity.

In any case, it would be nice to see the data behind claims of 300 year life! I have a Canon dye printer (9000 mkII) but can't wait to check the claim posted in this topic--I'll be 70 soon.

Light fading and gas fading correlate linearly with light intensity or gas concentration over reasonable ranges. So, for example, double the light level and you increase the rate of light fade 2x, or double the concentration of ozone and you double the fade rate for ozone sensitive colorants, and these known behaviors allow researchers to design effective tests for specific print degradation mechanisms. On the other hand, color changes due to dye diffusionversus relative humidity often have a discontinuity due to what polymer chemists call the glass transition temperature of the polymeric image binder layers. But you can fix the test at a known humidity level (say 80%) and then the change in visual appearance can be measured using colorimetry, for example, and it will follow an exponential decay curve.  Of course, there are always some caveats to any of these test methods -e.g., deviation from linearity at very high light intensities or very high gas concentrations that limit how much one can safely accelerate a particular reaction.

Anyway you have the right idea, and there are valid test methods that allow researchers to determine the relative strenghs and weaknesses of various print process as they relate to different failure mechanisms.  And in some situations we really can give an accurate predictions, but only when certain assumptions are made about relatively steady state environmental conditions, the desired condition of the print at the test endpoint (i.e, good, fair, poor, etc) and we further confine the answer to just one degradation factor.  The common problem is that those asking "how long will my print last" rarely want to hear these details, and so manufacturers are free to give about any answer you'd wish to hear. That's what the problem is with the 300 year claim that started this thread.

Even acid and lignin-filled newspaper stock and cheap litho inks can easily last over a century! One just has to provide reasonable storage and display environments and accept a fair amount of visual change in appearance and increasing physical fragility of the newspaper over that time period. But you will still have a functional object. the images and text won't be totally unreadable.  Hence, the question photographers should be asking about the print processes they choose is not "how long will it last?" but "how well will it last" under less than ideal circumstances as time goes by.  Some processes are much more durable and hold their initial properties much better than others over time. That's what serious printmakers should be striving to learn about. It's pride in one's craft that is at the heart of both initial print quality and print longevity issues, IMHO.

kind regards,

Mark

http://www.aardenburg-imaging.com

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