Ever paint a very wet watercolor painting on 140 lb. paper only to end up with a warped wobbly painting? There is a very simple cure to this problem. Iron the painting! This works well with paintings done on quality 100% cotton rag watercolor paper. That is 100% cotton rag ... cotton ... yes, you can iron cotton. Just iron on the back.
1. Starting with a wavy watercolor painting, place it on the ironing board, or multi-folded smooth cotton material on top of art table. Preheat your iron, NO steam.
2. Flip the painting upside down and iron.
3. Allow painting to cool and you will have a flat painting ready to frame!
Give it a try! If you're nervous about it, test it on a practice painting.