Local artists Mark Sink and Kristen Hatgi embraced the techniques of mid-19th-century wet-plate collodion photography (photo plates are exposed and developed while still wet, crystalizing light and capturing pure images) when they snapped the shots for Light and Time, their current photography exhibit at Denver's Rule Gallery. Through this weekend only, catch the duo's whimsical, black-and-white still lifes, portraits, and nudes, as well as Sink's rare collection of Andy Warhol photos. Tue-Sat noon-5 p.m. Rule Gallery, 227 Broadway 303-777-9473, free