May I add # 7 To Ansels excellent treatise, flash photos can sometime
interupt a visitors viewing pleasurable experience especially if viewing
artwork.

Len Hambleton - Objects Conservator
North Carolina Museum of History
5 East Edenton Street
Raleigh NC. 27601-1011
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919-715-0200 x244
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Opinions expressed in this message may not represent the policy of my
agency

> -----Original Message-----
> From: J. Ansel [SMTP:[log in to unmask]]
> Sent: Friday, January 16, 1998 12:15 AM
> To:   [log in to unmask]
> Subject:      Re: effects of Electronic Flash on paper, paintings,
> etc.
>
> Without light, objects cannot be seen, so some level of light is
> necessary for display.  How much light and for how long is the
> question.
>
> Consider the amount of energy released with each flash of a modern
> "snapshot" camera.  The energy comes from a small battery (which lasts
> hundreds of flashes) and thus the energy released in each flash is
> absolutely minimal-especially when compared with sunlight or even low
> room lighting.
>
> And since the inverse square law applies, the distance between the
> light
> source and the object remains important.  At two meters 1/4 the energy
> strikes the object than at one meter, at three meters 1/9th, at 4
> meters
> 1/16th and so forth.
>
> Plus objects in cases or behind glass are further protected because
> some
> light from photo flashes is reflected off the glass (especially if the
> light strikes the glass at an angle) and light can also be absorbed
> (usually very little however) and certain wavelengths of light can be
> blocked by the glass if the glass is designed to do such.
>
> A flash at four or five yards puts very, very little energy on an
> object
> and has very little effect, if any.
>
> Museum folks outlaw flash photos because they:
>
> 1.   Don't like the flashes, as suggested by others on Museum-L.
> 2.   Don't want folks to take pictures and use them for commercial
> purposes.
> 3.   Don't understand how little damage a snapshot flash can do.
> 4.   Feel photos taking is not in keeping with the decorum of their
> museum.
> 5.   Have an incredibly precious and delicate object, in which case it
> probably should not be on permanent display anyway.
> 6.   Abhor ancient exploding flash bulbs, as described by Patrick
> Boylan.
>
> It's good if people take photos.  Photos enhance interest and help our
> visitors bring the museum experience home.  Our visitors want to take
> photos and why not!  Plus all those amateur photos aid your marketing
> efforts.
>
> Regards,
>
> Joe Ansel