Question: So I noticed that some of the posters I've had in frames for about a year have started to develop some 'ripples' inside of the frame. They aren't super noticeable, only under certain lighting conditions. Also, it doesn't seem to actually be affecting the poster once I remove it from the frame, so I hope that it isn't anything permanent. In other words, when I took one of the posters out of the frame and laid it down, the ripples were gone. I'm using HPF frames (archival or deluxe, depending on the poster), and am using the back tensioners (or whatever they are called). In any case, I'm wondering if this is normal?
It seems to be only happening on the posters that are on thinner paper, and only after a period of time. I like to display my posters, so I don't really want to rotate them. I had planned on keeping them framed/displayed for years, but am concerned that it could result in damage if this is an actual problem. Any ideas?
Also, none are in direct sunlight and are kept in climate controlled rooms (ranging in temp from 68-75 F during the day).