Originally Posted by NiLuJe
@mstefanski: It's the default (well, not exactly, but unless you want me to start rambling about e-ink internals...) on the K4/K5. 5 pages of flash-less refresh, then a full refresh. You can *disable* it on the Settings page (ie. always flash).
Keep in mind that this heavily depends on the temperature of the controller. It will fall back to full flash if it's too hot.
There is bad ghosting when too cold too (high oil viscosity in the eink beads). It really should do full flash then too.
For highest contrast on a K5, it sometimes takes THREE full-flash updates. You can force refreshes from SSH to see that effect.
And I wrote some code that does intensive scanline redraws, so even after triple update in ideal conditions, I can write both clearly visible "blacker than black" on black backgrounds, and "whiter than white" on white backgrounds. Just the nature of eink. But still MUCH better than the ghosting on school chalkboards from when I was at University. They did not get "full refresh" (washed) during lectures.