While nailing 19th century conventions and language are critical to replicating life in 1860s New York City, the new BBC America crime drama COPPER has another edge: Clothes painstakingly hand-tailored and sewn from only fabrics available at the time. Costume designer Delphine White led the design and production of “600 dresses, frock coats and union suits” for the show. But it’s not all meticulous reproduction and corsets—find out what Mick Jagger and Robert Mapplethorpe…