Quantifying light exposure

Regarding Karen Potje's 19 May posting:

At the Ackland Art Museum, University of North Carolina at Chapel
Hill, I recently worked on developing a rational policy for the
exhibition of light-sensitive works of art, also based largely on
the information in Colby's article.

Our museum is open to the public almost 40 hours per week, but when
I added it all up, I found that the gallery lighting is turned on
nearly 60 hours per week.  Sporadic attempts over the years to
lessen this number have failed.  Recent discussions with other
museum staff members led me to the conclusion that this was not
likely to change.  There is a lot of traffic in the galleries during
"business hours" when the museum is closed to the public--cleaning
staff, preparators, curators, as well as a large number of school
groups who make their appointments for tours during "off hours".

So my calculations for lux hours/per week are based on the
assumption of 60 hours of light per week. This, of course, means
fewer or shorter exhibition times as we "ration" the total number of
exhibition hours to which we are willing to subject a work of art.
We have not, at this point, asked borrowing institutions to
calculate the number of hours their gallery lighting is turned on,
but I work on the assumption that it is as comparable to the
situation here.  (Actually, what I worry about more is the
unspecified time loaned objects may spend in work areas in other
institutions, with fluorescent lighting.)

Lyn Koehnline
Paper Conservator
Ackland Art Museum

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                  Conservation DistList Instance 11:95
                   Distributed: Friday, May 22, 1998
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