Against the Newtonian view of color, according to which the world is colorless and colors are subjective sensations, phenomenologists keep insisting that colors are in the world. In order to defend this view of the "being in the world" of colors, this paper tries to elucidate the essential spatiality of colors on the basis of James's thesis of the intrinsic spatiality of sensation, Katz's phenomenological description of various spatial characters of color, and Gibson's ecological optics. The noticeable correspondence between Katz's phenomenology and Gibson's ecological optics indicates to us a possible way to an ecological phenomenology of colors.