In the early seventeenth century, there existed a myriad of theories to account for color phenomena. The status, goal, and content of such accounts differed as well as the range of phenomena they explained. Starting with the journal of Isaac Beeckman (1588–1637), this essay inquires into the features and functions of conceptual reflections upon color experiences. Beeckman played a crucial role in the intellectual development of René Descartes (1596–1650), while at the same time their ideas differed crucially. Early corpuscular conceptions of colors cannot be reduced to the mechanistic variety of Descartes. Moreover, the optical rather than corpuscular features of Descartes’s understanding of colors were essential. A stratification of conceptualizations is proposed that is grounded in various problem contexts rather than philosophical doctrines, thus opening a way to interpret the philosophical parts of color worlds in a more diverse way.