Pre-painted metal is a metal on which a material such as paint has been applied by the coil coating process to form a protective film. Coil coating is a continuous process in which a coil of metal (steel or aluminum are common substrates) is unwound and both the top and bottom surfaces are cleaned, chemically treated, and then primed and /or painted and oven cured.  A wide range of coatings are in use, developed in order to provide different levels of durability and performance and to satisfy distinct aesthetic requirements.