Dictionary.com defines tulle as "a thin, fine, machine-made net of acetate, nylon, rayon, or silk." Tulle can add a crisp and airy accent to hats, wedding decorations, ballet tutus and dresses, expanding the visual effect of your clothing without increasing its weight. If tulle droops, its effect is greatly reduced. Tulle requires stiffening to maintain the shape you want it to have.
Hand-wash the tulle with cold water and laundry soap. This will ensure that no dirt will adhere to the tulle when you stiffen it. Hang up the fabric in an open, well-ventilated space and let it air dry.
Once the tulle is completely dry, cover each side of the tulle with a thin, even layer of aerosol starch or stiffening spray. Allow 30 to 90 minutes for the spray to dry.
Take down the tulle and test its stiffness. If you wish the material to be stiffer, add additional coats of spray as needed.
Test-wash a small section of the tulle before you wash the rest of the material, to ensure that the washing will not damage the fabric.