Things You'll Need
Four heavy books
Posters are great as souvenirs and memorabilia, but if you buy a poster away from home or order it online it's possible that it will arrive at your home in less than perfect condition. Posters can also develop wrinkles after hanging in a frame for some time. While a wrinkled poster will probably never be as good as new, it is possible to work some of the wrinkles out of it before hanging it.
Lay the poster face down on a flat surface. A hardwood floor or a counter top is perfect. If you must lay it on carpet, lay something flat beneath it, such as a piece of poster board.
Stretch the poster out completely and place heavy books on all four corners to hold it flat. If the wrinkles are slight, this will work out many of them.
Iron the poster. If there are major wrinkles in the poster, the easiest way to remove them is by ironing them out. Place your iron on its lowest setting. If the iron is too hot, it can damage the poster.
Place a piece of fabric over the poster while you iron. The fabric will protect the poster from the heat.
Mist the fabric lightly with water. When you iron over it, the water will create steam that will help remove the wrinkles from the poster.
Take your poster to a framing shop. If all home efforts fail, framing shops often have heat presses on the premises that will take out hard to remove wrinkles.
If your poster has wrinkled inside a frame, it is more than likely due to the fact that there is too much space between the poster and the back of the frame. Cut a piece of cardboard the same size as the frame and place it behind the poster in the frame. This will give the poster a nice flat surface to press against and prevent future wrinkling.