Interlux Flattening Agent for 1 Part Finishes A Flattening Agent specially formulated for mixing with Interlux one-part finishes Brightside Polurethane and Yacht Enamels and varnishes Schooner Gold, Original, Goldspar and Schooner to produce a variety of gloss, satin or matte effect finishes. For interior and exterior use. The addition of Flattening Agent to a finish or varnish will not affect the drying or overcoating characteristics of the product. It will not affect the durability of the fini