Frame lights on paintings

I remember reading something quite a while back about the problems
associated with frame lights on paintings.  But I have been
searching without success for the reference/ references.  Can anyone
refresh my memory, please.  Many thanks.

Wendy Claire Jessup

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                  Conservation DistList Instance 10:26
                Distributed: Tuesday, September 10, 1996
                       Message Id: cdl-10-26-016
                                  ***