Ellen, Jean-Luc's recommendation to follow the recommendations of the CCI Notes is an excellent one, and I can only add to that some personal thoughts from practical application of many types of light-mitigation materials. When I began using filtering film, it was mostly in the form of roller shades; the thought was that installation was easy (although the first vendor insisted on having their own installer do it -- what a waste of money!), and shades could be raised if need be, for periods of maintenance or changing exhibitions. I found a spot where a couple of units could be installed, and waited to see the reaction of our director and board members. No one noticed -- a good thing. When informed about the installation, and queried about the appearance, the board's consensus was that the medium-density film was "too bright". So we went with the denser film, which was what I wanted all along.
In other light-filtering applications, I used non-roller film panels, exterior acrylic panels with film applied (a bit risky, but they lasted twice as long as the five-year expected life), and (semi-)rigid acrylic panels, suspended on double-hung window sash, and even one adhesive film applied to a modern window. I also used shading fabric roller shades, too, if you would like to hear about that. There were various installation challenges, such as century-old bronze window frames, two hundred year-old woodwork surrounding some windows, and so forth. Although I had heard that removing failing, old film was a tough and risky job, I was fortunate in never having had to do it. I was also fortunate that neither the director nor the board members complained about the look of the filtered windows -- even from the exterior. Maybe that was just luck, but I'll take it.
If I may be of further assistance, please don't hesitate to get in touch -- abmacleish@verizon.net
Best,
Bruce
------------------------------
Bruce MacLeish
Curator Emeritus, Newport Restoration Foundation
Cooperstown NY
------------------------------