Interlux Brightside Flattening/Gloss Reducing Additive is designed for use with Brightside one-part polyurethanes or Interlux Enamels. Use 4 to 8 oz per quart, darker colors require more. The flattening agent helps to reduce the natural gloss that Brightside is known for. Many yard workers and amateur boat painters use the Gloss Reducer for interior paints (cabin finishes), home projects, and other applications where a bright, glossy finish is not desired.