Natural lighting can also be let in through a clerestory window level and
bounced down off of a barrel-vaulted ceiling.  The Metropolitan Museum of
Art does this in their medieval exhibition room.  They have an excellent
system of both natural and artificial light that is not only safe for the
objects but is pleasant for viewing the objects.
        Also, limiting the daily exposure by turning lights on only during
exhibition hours or, having visitor-activated lights helps.  Increasing the
distance from light source to object helps, as well.
        High-quality filters, though expensive, can be put over windows and light
sources, as opposed to over the actual objects. 
        Good Luck!

Elizabeth Jablonski

At 12:46 PM 1/25/98 +0100, you wrote:
>Celebposter schrieb:
>> What is the consensus here about natural light in galleries?  If it is
>> filtered and indirect is there any danger? It does give better color.
>> Building a new space and want to know if I am better off with a black
>> box.
>
>Dear Anonymous, dear list members,
>
>I am resending this message because it was returned by unknown reasons. It
think 
>this subjects is worth being discussed again and again, because I met many a 
>people in museum who were thinking that the problem can be solved by a
luxmeter 
>alone.
>I am nothing but a publisher, but I like to stress these facts (I hope they 
>are):
>
>As newer research has shown, UV damages are a matter 
>of time (!)
>and dosis. 
>Of course, also of the material. 
>
>So it depends 
>what you want to show 
>under which circumstances.
>
>It could be shown by an Institute in Hamburg that UV-damages reach a certain 
>maximum, and after this date, the damages are neglectible. This happens
quite 
>fast and can be absolute bad for newspaper, prints etc.
>But take a Renaissance painting hanging 400 years quite often in direct 
>sunlight: this has reached since centuries its final amount of UV damage.
On the 
>other hand, prints and drawings from the 20th cent. have mostly not
reached this 
>peak and shoud be preserved under the best circumstances. This means:
Putting a 
>UV-light eliminating glass in front of a 15th cent. painting does not make
any
>sense (HAVE A LOOK ON THIS INTO OUR NATIONAL GALLERIES!). 
>The newer paintings and graphics are to be saved! Glas in front of real 
>old paintings may only be treated under the aspect of security.
>
>Also paintings can be damaged heavily by sunlight. Some artists used
"secret" or 
>bad mixtures for oils and varnishes, so be careful. Sunlight for older
paintings 
>may seem the best for the eyes of the visitors, but keep in mind the above
said 
>and that sunlight can also mean lots of troubles for your climatic system. 
>Modern architects knowing the wishes of conservators are playing with the 
>sunlight by refracting it by walls to the hanging areas. This is much better 
>than curtains or UV-Filters (films or glasses) in the windows. 
>
>A blackbox is not the alternative.
>
>An additional simple system may be adopted by replacing the endangered
objects 
>from time to time with others from the deposits. This may be also
attractive for 
>visitors (because they see different objects each time they visit the
gallery), 
>but give them a hint that a specific objects was taken into the deposits for 
>conservation reasons.
>
>The February issue of MUSEUM AKTUELL will deal on light in museums and 
>galleries. The mentioned institute will have an article there on the
daylight 
>problems. But it's written in German.
>
>Hope this helps.
>
>Dr. Christian Müller-Straten
>
>Verlag Dr. C. Müller-Straten, Kunzweg 23, D-81243 München,
>Tel/Fax: 089-839 690 43, http://WebMuseen.de/VERLAGCMS
>MAGAZINES AND BOOKS IN MUSEOLOGY (GERMAN/ENGLISH)+ GERMAN THESAURI
>
>