This essay deals with the form and function of color in comics, a strongly undertheorized aspect of graphic storytelling. It makes a plea for a holistic approach of color, whose use cannot be separated from the system of narrative in general. From a methodological point of view, it focuses less on the opposition between black and white and color, which is difficult to maintain for in-depth analyses, than on the shift from one system to another. It discusses two main examples that in the 1930s have similarly undergone such a paradigm shift from the monochromatic to the multichromatic, one European (Hergé) and the other American (Herriman).