Color-color plot for the two radio relics at high-resolution (7″). Left: Few points of the NE relic lie below the power-law line, consistent with a mostly power-law spectrum; some extend into the “concave” spectrum region. The coloring shows how the outer edge and the bright bar both fall mostly on the power-law line, with no sign of spectral steepening. Right: SW relic shows steepening at lower spectral indices, but still presents multiple points representing a flattening spectrum.