Starting with A. Rüegg's book Polychromie Architecturale, the American-born chemist studied the recipes of all sixty-three shads that Le Corbusier developed for Salubra between 1931 and 1959. In 1998 she founded the pigment company kt.color in Uster, near Zurich. In 2000 she received an exclusive license from the Fondation Le Corbusier to produce the sixty-three colors as artists' colors and wall paints (interior and exterior) and to distribute them worldwide. Since then, she has been expanding production, assembling additional color recipes (more than 900 in all), developing a comprehensive palette of whites, working with historically important colors that the industry has neglected (e.g., Yves Klein's ultramarine blue and Semper's Pompeian red) but whose use still makes sense today, not only for aesthetic reasons but also economic and ecological reasons. In addition to producing pigments, Katrin Trautwein is a consultant to architects and developers and is asked for second opinions; she also offers regular seminars for architects, interior designers, house painters, and so on, on the subjects such as crafts; color design; pigment colors; principles of materials; the color concepts behind Le Corbusier's palette; light and shadow colors; new objects, new color concepts, and so on. She is called in for restoration projects to determine colors and provide materials (Le Corbuser's Maison Blanche, Lux Guyer's Saffa-Haus, and others); she gives lectures throughout Europe and in the United States.