The current exhibition "On the Edge" of three artists working with photography at Spalding Nix Fine Art is a blow-out of pattern and blazing, juicy color. Though the three artists — Atlantans Lisa Tuttle and Spencer Sloan and New Yorker Landon Nordeman — take very different approaches to subject matter and to photography itself, they are united in a surface style beholden to enough visual action to keep your eyeballs engaged.