Twilight -- A Circular Color Map
The colors begin with off-white, ranges through blue to off-black, then to red and back to off-white. Perceptual lightness contrast and color contrast are uniform over the whole value range. The colormap prints as perfect white-black-white, and works equally well with color blindness.
The colormap was designed using the viscm colormap design tool by creating a perceptually uniform colormap from off-black to off-white through red, and another colormap from the same off-black to the same off-white through blue. The files red.py and blue.py are still editable through viscm.