Clear organic coatings are used to prevent tarnishing of copper and its alloys in applications ranging from the purely decorative to those which are subject to relatively harsh environments and wear. There are numerous proprietary products, from basic organic polymers (e.g. acrylic, epoxy, nitrocellulose) to coatings which provide special properties, such as ultra violet absorption, outstanding hardness or rapid drying. Some coatings dry in air at room temperature while others require controlled baking operations. A series of comprehensive tests was made in America to determine the capabilities of these coatings and to compare them. Coated samples were subjected to a series of chemical and physical tests, including determination of substrate color. The samples were exposed to a variety of environments and certain properties and appearance were again assessed. Changes in properties and appearance provided an indication of the protection afforded by the coatings and several tables show the results. -- AATA