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Author Topic: How do you tell if a paper is acid-free or has OBA's?  (Read 11410 times)
Alan Goldhammer
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« Reply #20 on: November 24, 2009, 01:54:47 PM »
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Quote from: Wayne Fox
That leads me to another thought ... if the OBA's convert the invisible UV spectrum of light into a visible spectrum, wouldn't displaying the print under UV absorbing glass negate this effect almost entirely, so using an OBA paper has no advantage?  I researched this briefly a couple of times and didn't find an answser.
It is entirely possible but would depend on the cut off of the UV filter and the nature of the OBA compound.  I've not been able to find any description of what molecules are used in papers hence cannot say for sure whether their activity would be negated.  It ought to be a pretty easy experiment to do.  Get some of the UV-Acrylite (forget the tradename) and put it over a sheet of OBA paper; shine a black light and see what happens.  I suspect that if the cutoff is close that you will visually see the difference.  I presume that these are proprietary for each manufacturer (but I've also not done any type of patent search either).  There are lots of cool fluorescent molecules out there and one could do some very interesting things with them (I remember back in my lab days using a variety of different molecules in my biochemistry research).
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Alan Goldhammer
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« Reply #21 on: November 24, 2009, 02:11:18 PM »
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Quote from: Wayne Fox
Certainly if trying to produce museum quality maximum archival prints then acid free non OBA papers may be in order.  But there is plenty of evidence that OBA containing papers, as well as other paper making techniques are more than adequate for extreme print longevity ... certainly decades longer than any color process we had as little as 10-15 years ago when the only real option was silver halide technology.
Absolutely, this is the major advance that digital photography has brought to us all.  Pigment inks move us into a realm that the dye based photography of the past cannot (I don't include B&W printing here as the archival qualities are well known).

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I offer one comparison example. According to Wilhelm permanence ratings images printed with an Epson 7900 on Epson Exhibition Fiber, which is not a 100% acid free rag based paper (it is wood pulp based) and contains OBA's is rated at 90 years when displayed under glass, 150 years when displayed under UV filtered glass, 44 years when not protected at all and greater than 200 years  in album dark storage, and this last test includes paper yellowing.  Compared to Somerset Velvet which is a 100% acid free cotton rag paper with no OBAs (and is a gorgeous paper) - 62 years framed under glass, 128 years under UV glass, 37 years when unprotected, and >200 years dark album storage (which again includes paper yellowing).
I think the Aardenburg data shows the same results.  I was surprised to see some of the matte papers lose color at a much faster rate than a coresponding glossy paper from the same company.  Well worth looking at the data (and supporting the effort) as you can see the time decay data for each individual color square (some colors deteriorate faster than others).  Of course B&W digital prints are more stable as the blacks are carbon based and there is very little color used in their production.  

I for one and both happy and frustrated that we have so many great papers to print on (the frustration comes from the old aphorism, updated to:  "so many papers, so little time").
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Mark F
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« Reply #22 on: November 24, 2009, 11:05:37 PM »
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Wayne, I take your point and very much appreciate your, and everyone else's comments.

Quote from: Wayne Fox
But as far as "the jury is still out" statement,  this is true of anything to do with inkjet printing in general, and in fact is more applicable to inkjet printing and the inks themselves than it is to the OBA questions raised in this thread.  OBA's have been used in papers for a lot longer than the ink's we currently use, and while there is still some "controversy" regarding their affect, we probably know more about them than about the rest of the current inkjet process ... after all it is still a very new technology and all we have to go on are accelerated aging test.
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Mark
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