A while back I was asked to search for historic art for a very old building. I found some in the library archives. Upon having it made into an appropriate size, we had the glass that was going to cover the photo protected with a UV filtered glass. This can be clear as well as tinted. When you’re spending the time to do all the work, it makes sense to have the picture protected. This will reduce any fading. Its a really good idea to consider if you have some art going in an area with much sunlight.