Winsor & Newton Art Masking Fluid is a must-have watercolor medium for artists who want crisp edges, protected highlights, and confident layering. This easy-to-use liquid resist lets you mask out areas of your paper before applying washes, so preserved sections stay brilliantly white or retain underlying color. The fluid flows smoothly from a brush or applicator and dries quickly to a flexible film that peels away cleanly once your paint is dry. Ideal for watercolor, gouache, and ink, it’s especially helpful for fine details, sparkling light effects, and complex compositions where control matters. Whether you’re building landscapes, botanical studies, or mixed-media work, this medium gives you reliable protection and professional-level precision.