SALEM - Joni Sternbach has perfected a form of time travel. To get from present to past she uses nothing more complicated than surfboards and tintypes. Surfboards you know about. Tintypes? They were a popular 19th-century photographic process that printed an image on metal, most often iron or steel (Sternbach uses aluminum). Cheaper than daguerreotypes, they were like that format in making images that were unique rather than reproducible.
Sternbach photographs surfers posing with their boards and prints the results as tintypes. In fact, she takes a portable darkroom to the beach and develops her images right there. Forty-seven examples, along with two dozen vintage tintypes, a display explaining that process, and a cheerfully battered surfboard make up "SurfLand: Photographs by Joni Sternbach," which runs at the Peabody Essex Museum through Oct. 4. There's also a monitor playing a video of surfers that Sternbach made with Bruce Milne (the sound of the surf is very soothing).