Things You'll Need
White gesso or acrylic gel medium
Cardboard is readily available for artists to use as a painting surface. It is also an economical choice. Many famous artists, such as Toulouse-Lautrec, often painted on cardboard. In order to make the best use of cardboard for painting on, however, it should be primed. This is because cardboard tends to absorb paint. Cardboard will also last much longer if it is properly primed.
Trim the edges of your cardboard if necessary. Make sure that the edges are all intact and that the corners are square. If you need to trim the cardboard, do so with the X-Acto knife. Scissors will not make a straight enough edge.
Mix two parts PVA glue with one part water in the plastic cup. Stir the mixture with the stir stick until it is thoroughly mixed. Cover the entire surface of the cardboard with the PVA glue mixture. Coat it evenly and then let it dry completely. This will prevent your painting from warping.
Cover the entire surface of the cardboard with the PVA glue mixture. Coat it evenly and then let it dry completely. This will prevent your painting from warping.
Cover the dried PVA mixture with white gesso or acrylic gel medium. Use gesso if you want a white background for your work and use gel medium if you prefer the brown cardboard color to lie under the colors you apply. Let this primer coat dry. You can now paint your cardboard as a canvas.
In order to protect your fragile cardboard painting you can mount it on museum board or foam core.