Aging Prints or Paper
Burnt Umber or Brown Acrylic Craft Paint
A soft brush or a sponge
Aging prints and paper is a very simple process. If you really want an aged appearance, crumple the print of paper in your hand. Not too much just make a few creases. You may also tear off corners making sure you tear from the top to leave the torn edge on the part you will be aging. Prints on heavy paper do not work well. Always practice on a throw-away first.
Mix a small amount of paint (depending on how large of an item you have to age) with water in an old container. A good rule of thumb is 1 part paint to 4 parts water. Mix well enough so the paint is transparent yet will stick to paper. With your brush or sponge dip into the paint mixture and apply to the paper darkening the torn edges and creases. Lay flat and if small enough, between two boards or heavy objects to flatten. If the paper curls you can press with an iron between a cloth to smooth.
This is a simple technique but adds a lot of character to your collage or decoupage.