Dear List,

A quick study of the characteristics of the energy spectrum would
probably be of some help here.  Suffice it to say that light -- both
visible and invisible -- is radiant energy and that radiant energy can
damage virtually all museum-related materials.  Ultraviolet radiation
represents one end of the light spectrum, visible light occupies the
center, and infrared the opposite extreme from UV.  While, ultraviolet
radiation causes more damage to most museum materials than light emitted
at longer wavelengths, it can be said that all light can cause serious
photochemical damage in museums.  In dealing with windows it is important
to assess the amount and characteristics of visible light as well as UV
radiation entering the space, and its potential danger to affected
materials.  There is no question that visible light will affect certain
papers, dyes, inks, paints, wooden and other organic surfaces...and the
list goes on.  Further, infrared radiation heats reflective surfaces, and
this can cause serious damage to organic materials as well.

As I said, it is important to assess particular conditions in the areas
of exposure before you decide on the kind of window treatment to
purchase.  Window films exist that are reversible and that filter UV and
varying levels of visible and infrared radiation as well.  Further,
pull-down screens are available with varying levels of opacity to visible
and infrared radiation, and they can be fabricated to be operated
manually or electronically.  The choices available are manifold, and
varying combinations of screens and films can address virtually every
need.  I will be happy to refer you to national manufacturers and New
York area vendors, but would prefer to do so off-line as I think that the
List should be for the exchange of general information rather than paid
or unpaid advertising.

Good Luck!

Oliver Hirsch
Hirsch & Associates Fine Art Services, Inc.
New York

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