Picture Framing - happens when ink collects on the blanket outside the sheet perimeter. Picture framing is a visible effect caused by the other problems such as ink emulsification, tinting, toning, scumming, misting and piling.
A test to determine if picture framing is caused by a chemical problem, or a plate processing problem: use a good honing stick or pen ink eraser. Scuff a fairly large mark in the non-image area, outside the perimeter of the paper. Treat that area with a good plate cleaner and gum it. Clean all ink off the blanket and dry thoroughly. Run 500 sheets and stop the press. Inspect the blanket in line with the marked area. If the marked area is clean on the blanket, but you can see ink building up around the area, you have a plate processing problem. If the blanket is starting to build up with ink, and you cannot find the marked area, the problem exists on press.