Originally Posted by Jadon
The way I imagine it is having a framed newspaper clipping, and laying a piece of colored film on top of the glass. Without the film, white light hits the paper and bounces back with a certain efficiency. Add a colored filter, and only the red (or whatever) fraction of light passes through to be reflected. You're losing most of the light, so adding filters reduces brightness, just like sunglasses do. But the screen under the filter is the same as always, so it's bistable and will show the last screen even without power, and power requirements are no higher, and it's not LCD. A colored screen will look darker than a b&w one, though, so you might want more light to read by.
I remember that a few months ago, at a trade show, E-ink showed a prototype of their post-Pearl screen technology, which will offer far better contrast, around 20:1 if I remember well. Obviously they will use that in their color screens, which is why in the spec sheet of Triton the contrast is the exact same (10:1) as in the spec sheet of Pearl, despite the three added color filters: