Painting is one of the last steps in building a wooden window valance. Choose the paint color according to the desired finished effect. You may opt for a color that matches the wall or decide to use a contrasting color that coordinates with the fabric of the window treatment. Apply a high quality spray primer, and allow the valance to completely dry. After the primer has dried, you can apply several light, even coats of spray paint. Allow the paint to dry thoroughly before you move on. Finally, apply 2 coats of polyurethane to finish and protect the valance, and allow everything to completely dry before you hang it up.