@pickyaxe: You can't? It's part of the waveform tweaking services e-Ink itself offers to its partner, AFAIK (aka., NDA-land).
As a gross oversimplification, instead of being tweaked for black on white, it's tweaked for white on black.
(Note that on Kindle, there are also extra trickery involving how the flashes are dealt with, and the frontlight level. I haven't seen traces of any of that here, but I haven't looked into it all that much, and I haven't had the device in front of me either
).