For the time being, they are stored in transparent plastic pocket folders.
I do intend to frame them later.
For framing, it's best to use spacers. That means, there is the poster, and another thicker layer of "cardboard-like" material on top of it, but with most the center cut out to show the poster.Leaving a "frame" shape.The spacer is to leave a gap between glass and the poster, so they won't touch. Also "breathing space."
Because I found that most posters if framed with glass directly touching the poster or artwork would cause it to develop mould.
I haven't asked around for acid free backing on frames, so you might want to look into that.
Some of my own paintings(watercolor, poster colors) have been kept inside transparent pocket folders since I was in Form 4 until now, and they still look great. No fading, no flaking. Of course I used good paint like Pentel watercolor from Japan.
Another toner printed piece of Sakura Wars by international comic artist Yazid which I got from him between 2000 and 2001, was kept inside a transparent CBE brand made soft document case. Everything looks great. Except a small part of the print seems to be have a bit of "glazed" result. Shiny on some colors at the bottom when viewed at an angle with lights.
As added precaution, if you have folders, please keep some dehumidifiers like silica gel or boxes of thirsty hippo around them.
http://www.learnaboutmovieposters.com/n ... ersize.asp