The 1861 collaboration between physicist James Clerk Maxwell and photographer Thomas Sutton was a landmark episode in the history of optics and photography, resulting in the famous "Tartan ribbon" image: the first permanent color photograph in history. This focused and incisive study from Maxwell scholar Jordi Cat reassesses this partnership, situating it within the histories of objectivity, experiment, and collaboration. Cat reveals that Maxwell and Sutton were closer to true partners than has commonly been assumed, and shows how their experiments illuminate the role of Victorian technology, representational practices, and modes of participation in Maxwell's natural philosophy.