I'm going to be putting together a temporary portfolio of pictures (all around the size 9.5 x 12 inches) going onto A3 card that will go into plastic sleeves. The prints I've got were all dried on a flat dryer and are a bit warped but nothing serious. Will a thorough blast of spray adhesive on the back and a couple of telephone books pressing it down give a print a good good flat mount? Or should I loosen the prints up first with a mild go of a steam iron? Any hints will be welcome.