This paper examines the theoretical foundations of the invention of color printing in the early eighteenth century, and their importance for the development of our modern intellectual property regime. In these years, the amateur philosopher Lambert ten Kate, the entrepreneurial printmaker Jacob Christoffel le Blon, and, to a lesser extent, the classicist painter Hendrik van Limborch collaborated on an experimental research program to reform the sciences and the arts, and came to believe that the same, Pythagorean harmonies governed the structures of human body, the diffraction of white light, and all other branches of knowledge. The culmination of their research program was Le Blon’s invention of color printing, an artisanal technology based on the mathematical laws of Pythagorean theory. This conceptualization of printmaking turned away from the early modern artisanal epistemologies that Pamela Smith has so eloquently discussed. While earlier artisans thought that their knowledge was embodied, and could only be acquired through long years of experience, Enlightenment printmakers like Le Blon came to sincerely believe that technological know-how could be reduced to mathematical statements. These mathematical statements could be disseminated and communicated easily; anyone could learn from a book how to do artisanal work. This was not a welcome development for artisans who earned a living from having a monopoly in their field. Le Blon considered the mathematization of artisanal work a risky proposition, because he feared that others would then be able to quickly steal and pirate his new invention of color printing. He therefore resorted to trade secrets, and also exploited, and even shaped, the emerging patent systems of the eighteenth century. My talk thus argues that the growing Enlightenment belief in the mathematization of knowledge did not give rise to the public sphere, or a Republic of Letters where knowledge was exchanged in a gift exchange. By putting artisanal knowledge on theoretical foundations, Enlightenment artisans contributed instead to the development of the modern intellectual property regime.