Riso Barycentric Color Atlas is an formal exploration of color mixing on the risograph. Twenty-four sets of three color combinations were chosen from thirteen inks (if you are counting that leaves 262 more, but most aren’t so interesting).
For each combination I printed 135 swatches grouped into six figures based on total ink coverage: 50%, 75%, 100%, 133%, 166%, and 200%. This means that colors of similar intensity are next to each other for better comparison. Each set of six figures is located on its own spread with the generous size of 6.25 × 36".
The swatches in each figure were organized using barycentric coordinates. These coordinates translate a point in the center of a triangle to a mixture of the three inks, located at each of the vertices. The closer a point is to a corner, the higher percentage of that corner’s inks are in the mixture.
The book also includes a table showing the percentages for each swatch, a gray ramp for calibration, and a die-cut swatch viewer for isolating individual swatches. The swatch viewer is housed in a tiny die cut envelope on the back cover.
The images here don't do the colors justice, especially all of the pages with Fluorescent Pink and Fluorescent Orange.
A full PDF of the book is available here.
Click here to purchase a copy. Purchase comes with a digital download of the figures to make your own tests.
I am currently working on an expanded "deluxe" edition of the book which will include pages with all of the preliminary color tests, and a 3D printed version of the truncated cube from the title page.
More Information on Barycentric Coordinates
Another way to think about barycentric coordinates is taking one unit of mass and distributing it on the corners of the triangle. The point on which the triangle will balance is the center of mass, or the barycenter.
