Will Polyurethane Ruin a Picture?

Polyurethane is highly toxic and should be handled with care. Make sure the lid is properly sealed between coats. ... If you're ready to seal a picture with polyurethane, chances are you're in the final stages of decoupage – the art of affixing paper to furniture, walls and decorative accessories.

How do you seal pictures on wood?

Dip a clean paintbrush into the shellac. Using long, smooth strokes, brush a thin layer of shellac over the entire wood surface. Allow the shellac to dry. Repeat until the wood is covered with four to eight coats of shellac.

Can I put polyurethane over paper?

Paper is very porus and will soak up any type of finish or sealer. You can't stop it from soaking up the first coat, you are effectively trying to paint a sponge. Just apply a second coat and see what it looks like. If still a little blotchy, a third coat will be required.