Do strobes damage 500 year old paper?

She's right. Electronic flash units put out a fair amount of ultraviolet light unless they're filtered, and almost any light is going to do some damage, however minimal. If the subject is valuable it would be good to minimize the exposures.

It's unlikely to damage the fibers of the paper that much but can affect the ink and especially any colored areas of an old book. You might ask White Lightening about how well the UV is filtered in their strobes, but they probably do have some.

You should be able to get a UV gel to cover the flash just in case.

Rosco makes them and im sure others do as well.

Here is a link i found for the UV gels http://www.stagelightingstore.com/s.nl/it.A/id.6234/.f

-ian

"I thought strobes were harmless."

Sorry John, strobes are rich in ultraviolet and can cause accelerated fading of inks. You must UV filter your strobe heads with UV blocking material. That said, since you are part of the staff and your documentation will act as a surogate for the original in many cases, you should continue to shoot the 16 shot mode for maximum quality. This will provide master files large enough and good enough to handle almost any need and prevent the object from being handled and photographed again. Just like you getting a chest x-ray, you want to minimize your exposure to ionizing radiation, but the diagnostic benefits outweigh the possible small risk. Do the photography once and do it right. This way you not only don't have to photograph it again but, more importantly, the object does not have to be moved and handled again which represents a far greater opportunity for mishap than the lumens of your strobes.

I know one shouldn't believe everything on the internet, but this bit of myth-debunking seems quite reasonable:

http://palimpsest.stanford.edu/byform/mailing-lists/cdl/1996/0724.html

The bottom line is, no, strobes are actually harmless.

It seems to me like a millisecond or so of UV is a decent trade for providing researchers in the future with good copy to use. It is really frustrating for a researcher to hear that important historical materials exist but will not be made accessable because it "might get damaged".

A bit more digging also reveals that many xenon flash tubes are internally coated with Gold to absorb most of the UV, too, which explains the yellow metallic tinge to some flash tubes (like the ones on my Elinchrom studio flashes).

That was a nice article, Alec. It shares the same attitude I've developed over the years. thanks!

I was told, years ago, that one flash from a compact camera was equal to 1 second of daylight. Obviously I was told wrong. The more I learn the more I realize I don't know.

I had come to the same conclustion, realizing that strobes have such a short duration, but nice to see the calculations.

Plus, many museums have what appear to be unfiltered fluorscent lighting, or sky lights, and most of us know that the ambient light over the period of a day, say, in Paris, amounts to a great deal of energy.

I do not think many of them have gotten the memo though.