Learning how to remove the wrinkles from a poster is easier than you might think. These methods require a little patience and care to work, so don’t try to rush through or you could end up damaging your poster instead. Also note that these DIY solutions are not 100 percent foolproof, so if you have a poster of particularly high value, consider using professional help instead.
Flatten the Poster
Before you try any more complicated methods, it is best to see if you can get your poster to flatten with just weight alone. Museums will frequently lay paper to be flattened beneath a sheet of glass or plexiglass, face down. Then, books or heavy reams of paper will be set on top to weigh it down. This process could take a long time to work, so be prepared to wait.
Iron the Poster
For a method that takes more care but a little less time, you can choose to try to iron out the wrinkles instead. Place the poster face down on top of a piece of cardboard set on a clean, stable surface or directly on an ironing board if it will fit. Cover the back of the poster with a normal cotton sheet and set the iron to its lowest possible heat without steam. Once the iron has heated up, move the iron over the wrinkles or creases without stopping. Check the poster every so often to see whether or not the iron has done its job.
Steam Your Poster
Most posters can be restored by using steam and pressure. Do not use the steam function on your iron and just go to town or you will ruin the poster. A better way to go is to hang the poster in the bathroom while you take a hot shower or just run hot water. Be careful to cover the poster with a cotton sheet that is gently clamped to it, as this will prevent too much water from getting into the paper, which will cause the ink to run.
Immediately get the poster with the cotton sheet between two planks of wood once it has been steamed. Remove the clamps and add pressure in the form of weight, like books. Give the poster about a week or two to completely dry out.
Frame Your Poster to Maintain Integrity
Once you’ve gotten your poster flat, you will want to protect it from further damage. Knowing how to frame a poster will help you to prevent any creases or wrinkles in the future. When you buy the frame, make sure there is enough even pressure in the back of the frame to keep the poster pressed against the glass. This will keep it from moving and becoming wrinkled again.