In an effort to create order within the color universe, he gave blue, red, and yellow pride of place in his hierarchy, explaining how these primary colors could be combined to create a multitude of shades in between.
Color printing was expensive at the time (which could emulate many colors possibilities in the way Pantone does). Although this color chart is exceptionally limited, I LOVE the shapes and stripes juxtaposition. How contemporary it appears!
Image source: printmag.com