Another thing to keep in mind is that it isn't 
just UV rays from sunlight... heat/improper 
temperatures is also an "agent of deterioration". 
(Oii, I feel like I'm back in Collection Mgmt. 
class again. ^_^)

For instance, if you have a regular, 100 watt 
incandescent lightbulb, it generates more light-- 
and more heat-- than a 40 watt incandescent 
lightbulb. A 40 watt incandescent lightbulb 
generates more heat than a 40 watt incandescent 
lightbulb.

Heat gets trapped behind glass, and builds up. 
Over time, it will affect the cel. Whether that's 
a few months or a few years depends on whether or 
not there's sunlight to help speed up the process 
with its radiation, and whether you keep the room 
lit for 10 hours a day, or for 2 hours.

That's one of the reasons why flashbulb 
photography is so often banned in museums, and 
why museums are so often dark, or use indirect 
lighting sources. It's to keep the colors from 
fading. Reds and yellows fade more quickly than 
blues... if you have paperback books that have 
been on a bookshelf in the sun for very long, you 
can tell the difference. Red type changes to pink 
very quickly; yellow fades to almost nothing. You 
might notice that in some restaraunts, if they 
have artwork on the walls by a window, the 
designers will go for pictures that make very 
heavy use of blue-green-and-black sorts of 
colors, which are more fade-resistant.

But that's a tangent. *^_^* If you want to enjoy 
your cels on the wall, by all means, please 
do. :o) It's no fun to buy something, and then 
not be able to admire it when you want to. But 
you have to understand that by being put on 
display, it will be exposed to heat, light, and 
radiation more than it would be if it was tucked 
away in a celbook somewhere. Keeping your cel in 
optimum condition sometimes means sacrificing 
personal preferences. But because the cel is 
*yours*, the judgment call is yours to make. ^_^

Take care,
-Cres