Film on paintings

For some reason at 2 galleries where I hang my paintings, the paintings are getting a film over them. it's a lightish grey colour although I have seen some reddish ones.
Has this happened to anyone else? and what can I do to get rid of it?
When I first started uploading my work I did individual targa files, now I bulk upload. Any known problems with bulk uploading targas?
Taxus Gustafson

I met with Taxus and found he'd set the canvas material shiny, which gives exactly the color cast he described. There are so many prim parameters that it is easy to miss something like that.

Anyhow, problem solved; just figured I'd pass that on to others.