How does light damage old books?
April 8, 2008 9:44 PM Subscribe
How does visible light damage ancient documents?
I just went to an exhibition of illuminated mediaeval manuscripts, and it wasn't very well illuminated. I'm told that light damages old books. How? Couldn't you get special filters?
I just went to an exhibition of illuminated mediaeval manuscripts, and it wasn't very well illuminated. I'm told that light damages old books. How? Couldn't you get special filters?
Best answer: Here's a summary. Short version: light triggers chemical reactions that degrade the paper and bleach inks, etc. All light (and not just UV) does this, so filters won't work (since a filter that doesn't admit any light can't be seen through).
posted by Mr. President Dr. Steve Elvis America at 9:59 PM on April 8, 2008
posted by Mr. President Dr. Steve Elvis America at 9:59 PM on April 8, 2008
Actually, upon further reading, there may be another solution albeit one with drawbacks. It appears that an oxygen atmosphere is a critical component of the dye fading caused by visible (but not UV) light. Since the UV can easily be filtered, this suggests that putting the objects in a case and replacing the air in the case with an inert gas should provide a stable display that can be illuminated at moderate levels as long as the UV is filtered.
Go ahead and design such a thing; maybe you'll make some money. Unless they alreay exist which wouldn't surprise me in the least. It seems an obvious solution.
posted by Justinian at 10:01 PM on April 8, 2008
Go ahead and design such a thing; maybe you'll make some money. Unless they alreay exist which wouldn't surprise me in the least. It seems an obvious solution.
posted by Justinian at 10:01 PM on April 8, 2008
Like the cases for the Constitution, etc. They use humidified argon gas... they used to use helium but argon is bigger molecules and tends to stay in the case better.
posted by smackfu at 10:14 PM on April 8, 2008
posted by smackfu at 10:14 PM on April 8, 2008
Well, the main question's been answered, but if you want some background info about what the curators are thinking...
smackfu is correct. The technology does exist to preserve and view fragile documents indefinitely, but there's a hitch. The first should be obvious from the Constitution link, and that's cost - really, I don't even want to think about the budget on that project. I can't help but notice it's not pointed out anywhere on the page, which is never a good sign ... In any case, that is VIP treatment even for rare docs.
Honestly, even for old, fragile, and rare documents, there is a spectrum of treatment - they're not all locked up far away from public eyes. My university has papyrus out in glass cases - standard museum treatment. In my history of printing class we handle medieval manuscripts and books on a regular basis, although not without coaching and only very, very lightly on an as-needed basis - admittedly, we only get to touch this stuff because we're library students, and there's a special collections staff member supervising us and the professor. But this is another one of the issues, and that's access - it's perfectly possible to preserve documents just about indefinitely, but is there a point if no one will ever see them?
Further, given the first two issues of cost and access, what do we make the choice of preserving? Because there's this stereotype about information specialists wanting to save EVERYTHING, but, uh, no. We have better things to do with our time, like making sure what's already around is well-organized and well cared for, a Sisyphean task in and of itself. Of course there's always new stuff to be archived and preserved, and sometimes it's not always what contemporary culture values (there's a coupon sitting on my desk now - I don't care about it, but will a socioanthropologist a century from now?), but it's naive to pretend that we don't have to make choices about what to save.
... Okay, that was way more than what you asked, sorry. IAAL/PIT,BNYL/PIT (I am a Librarian/Preservationist-in-Training, but not your &c). I got a little excited with the OOH ASKMEFI ABOUT MY JOB!
posted by bettafish at 10:53 PM on April 8, 2008
smackfu is correct. The technology does exist to preserve and view fragile documents indefinitely, but there's a hitch. The first should be obvious from the Constitution link, and that's cost - really, I don't even want to think about the budget on that project. I can't help but notice it's not pointed out anywhere on the page, which is never a good sign ... In any case, that is VIP treatment even for rare docs.
Honestly, even for old, fragile, and rare documents, there is a spectrum of treatment - they're not all locked up far away from public eyes. My university has papyrus out in glass cases - standard museum treatment. In my history of printing class we handle medieval manuscripts and books on a regular basis, although not without coaching and only very, very lightly on an as-needed basis - admittedly, we only get to touch this stuff because we're library students, and there's a special collections staff member supervising us and the professor. But this is another one of the issues, and that's access - it's perfectly possible to preserve documents just about indefinitely, but is there a point if no one will ever see them?
Further, given the first two issues of cost and access, what do we make the choice of preserving? Because there's this stereotype about information specialists wanting to save EVERYTHING, but, uh, no. We have better things to do with our time, like making sure what's already around is well-organized and well cared for, a Sisyphean task in and of itself. Of course there's always new stuff to be archived and preserved, and sometimes it's not always what contemporary culture values (there's a coupon sitting on my desk now - I don't care about it, but will a socioanthropologist a century from now?), but it's naive to pretend that we don't have to make choices about what to save.
... Okay, that was way more than what you asked, sorry. IAAL/PIT,BNYL/PIT (I am a Librarian/Preservationist-in-Training, but not your &c). I got a little excited with the OOH ASKMEFI ABOUT MY JOB!
posted by bettafish at 10:53 PM on April 8, 2008
Response by poster: Well bettafish, this is the collection I was talking about that I just (almost couldn't) saw. They suggest that this is a 'once in a lifetime' event and many of these books won't travel again.
Thanks for answers everyone.
posted by wilful at 12:12 AM on April 9, 2008
Thanks for answers everyone.
posted by wilful at 12:12 AM on April 9, 2008
You can see the effects of light for yourself if you leave (ordinary, modern) books exposed to sunlight for any length of time -- the colours on the bindings will start to fade alarmingly quickly. If you pull a book off the shelf you will often find that the colour of the spine, where the book has been exposed to light, is noticeably paler than the colour of the boards.
As Justinian says, ultra-violet light is particularly damaging. Occasionally we have to put one of our manuscripts under u/v light in order to read an erased inscription, but we never do this for more than a minute or two -- and u/v light on a page with gold-leaf illumination is a complete no-no.
However, I've been to some recent exhibitions where the light levels were ridiculously low -- so much so that you could hardly see the labels, let alone the exhibits. My own view is that the best way to exhibit fragile documents is not to exhibit them in semi-darkness, but to exhibit them for a strictly limited period of time. Unfortunately there are several reasons why that's not always possible: (a) some items are of such iconic importance (the Lindisfarne Gospels, the Book of Kells) that people expect them to be on permanent display; (b) items on loan have to be treated with special care, for reasons of insurance; (c) blockbuster exhibitions have to run for a considerable length of time in order to recoup their costs.
posted by verstegan at 2:27 AM on April 9, 2008
As Justinian says, ultra-violet light is particularly damaging. Occasionally we have to put one of our manuscripts under u/v light in order to read an erased inscription, but we never do this for more than a minute or two -- and u/v light on a page with gold-leaf illumination is a complete no-no.
However, I've been to some recent exhibitions where the light levels were ridiculously low -- so much so that you could hardly see the labels, let alone the exhibits. My own view is that the best way to exhibit fragile documents is not to exhibit them in semi-darkness, but to exhibit them for a strictly limited period of time. Unfortunately there are several reasons why that's not always possible: (a) some items are of such iconic importance (the Lindisfarne Gospels, the Book of Kells) that people expect them to be on permanent display; (b) items on loan have to be treated with special care, for reasons of insurance; (c) blockbuster exhibitions have to run for a considerable length of time in order to recoup their costs.
posted by verstegan at 2:27 AM on April 9, 2008
All of this applies to watercolor paintings also. Museums keep oil paintings on display constantly and with fairly bright lighting, but watercolors are displayed for limited durations, with dim lighting, and then stored away in light-proof storage. Watercolors in your house should be hung in rooms without bright or direct sunlight.
posted by beagle at 6:27 AM on April 9, 2008
posted by beagle at 6:27 AM on April 9, 2008
This thread is closed to new comments.
You can filter out visible light; it's called darkness.
But it's hard to see the book in a pitch black room so the compromise solution is a low level of diffuse light for a limited amount of time. It still causes damage, and the damage is cumulative, but the alternative is never looking at the papers.
Eventually, sadly, it is possible that no one will be allowed to see the actual physical object to prevent further light damage. Perhaps we'll have good 3-d holography by then.
posted by Justinian at 9:55 PM on April 8, 2008 [1 favorite]