Margaret,

There are various factors that affect the intensity of UV radiation.
One of the significant factors for you is the altitude at Taos. With
all other environmental conditions being equal Taos, at 6950 ft.
elevation will get approximately 22% more UV energy that a comparable
city at sea level. So you have to be aware of this as it will affect
the performance and durability of any UV film or protection system
that you choose. Also be aware that it is not only the UV (it is the
most damaging component of light) but it is also the total exposure to
light energy that you need to protect against as well. That is why
conservators will monitor and document both the total lumens and the
UV levels when we do a light survey in galleries, historic houses, and
storage areas.

There are many things to look at, such as the simple option to add
blinds to the windows and to keep them closed during the high exposure
times of the day (actually a solution used for hundreds of years!).
You could also consider having less light senstive objects and
materials in those areas. Also adding UV filtering media to any light
sources such as incandescent or flourescent lighting - especially
those adjacent or directed at art or objects is even more important
than the windows.

If these windows are your only light source for the galleries then you
could use a combination of approaches - window films and some
institutions have also used UV absorbing paints (Titanium dioxide
based paints absorb UV energy) - I believe the National Gallery of Art
did this in an atrium gallery.

For the type of window film system you are considering I would suggest
that you contact the architectural conservator at Monticello in
Charlottesville, Virginia. The last I heard Robert Self held that
postion (just tell him Dave Harvey sent you!). They've been using a
non-invasive UV window filtering system for more than 17 years so I
think that's a place to start in getting some good practical advice.

Cheers!
Dave

PS- Here is a link that lists all of the variables that affect UV levels:
http://www.who.int/uv/uv_and_health/en/



On 3/28/07, Margaret Bullock <[log in to unmask]> wrote:
> Dear Museum List members,
>
> I am working on screening down the natural light that comes in through
> windows at the end of one of our galleries.  The building is on the
> National Register so anything we do has to be relatively invisible from
> both inside and out.
>
> I have been looking at various films and etc. and find there is a
> bewildering array.  Could anyone who has had to deal with a similar problem
> please let me know what you chose to do and how it has worked out for you?
>
> Thank you very much
>
> Margaret Bullock
>
> Margaret Bullock, Curator
> Harwood Museum of Art
> 238 Ledoux St
> Taos, NM  87571
> 505-758-9826 x 110
> [log in to unmask]
> [log in to unmask]
>
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