Window films

In Conservation DistList Instance: 16:23 Wednesday, September 25,
2002, Anne Downey recommends against applying window films directly
to historic glazing.

Although it is true that there were problems in removing window
films when they were first introduced, our experience with the films
currently on sale in the UK is that they can be removed without
damaging historic glazing.  Again, in the UK, there are companies
that specialise in light control in historic houses and museums, and
we have found them very receptive to our concerns during
installation and removal of film.

Although we generally use the colourless Museum Film (which removes
99.5% of the UV), we are also using tinted (not reflective) films to
reduce visible light as well.  We find that even a film that
transmits only 35% of visible light can be acceptable to visitors,
provided that they can't see any untreated windows at the same time.
The film is also virtually undetectable from outside, so has no
effect on the appearance of the house.

Depending on the house, the window films are backed up with double
blinds (usually cream and dark blue) or shutters to exclude light
completely out of opening hours.

Barry Knight
Senior Conservation Scientist
English Heritage
London


                                  ***
                  Conservation DistList Instance 16:27
                Distributed: Thursday, October 10, 2002
                       Message Id: cdl-16-27-008
                                  ***