Hi!  I have a couple of cels framed.
There is a lot of light in my house, but there
is no direct light on the cels.  I havent
had any fading yet (knock on wood), but
they all have uv protective glass.  I think
if you have uv protective glass and it is not
in direct sunlight, you should be fine.
Dont take my word for it though.  I'd hate
to be responsible for ruining your cels.

Take it easy!

Ryan