The Daler Rowney Simply Art Masking Fluid forms a fast-drying, water-resistant liquid rubber film designed to protect paper areas from watercolor washes and ink layers. Applied easily with an old brush or cotton bud, it preserves crisp white highlights and complex fine details with maximum precision. Once your overpainting is completely dry, the rubbery barrier peels off cleanly or rubs away with a soft eraser without tearing the paper beneath.