Use special value viewers to see the lightness or darkness of your fabrics before you start cutting for your project. You can buy plastic value viewers in red or green, but note that these viewers work for fabrics that are not in the red or green color families. To use a value viewer, hold the viewer close to your eyes, like you would a pair of binoculars or 3-D glasses, and look through the viewer at your fabrics. You’ll see whether the palette you’ve chosen for your project has a wide variety of light, medium and dark fabrics.
Don’t have a value viewer handy? Use your digital camera on the black and white setting, lay the folded fabrics on a photocopier, or take the fabrics into an almost dark room and squint.