Quote:
Originally Posted by fjtorres
That is one way to do it but only if it relies on the Carta layer for its blacks.
But that isn't necessary. The color image might be totally independent.
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What you suggest hasn't been invented.
But no-one has invented such a colour device that can be totally transparent other than an LCD. An LCD actually needs a mirror and direct sunlight or a backlight and diffuser. It's got no native colour*. It has polarisers which attenuate light. It requires power to maintain the image. Greys are partial rotations of polarisation, black is 90 degrees to the polarisation of clear. Colour is a dyed filter layer aligned to the monochrome pixels. For well saturated colours the R, G and B filters need to block more of the colours not the desired R, G or B. So light losses can be well over 50%.
The LCD part is actually superfluous if you have eink, as that will provide the White (instead of clear), black and greys, just like the LCD, except there are only 14 grey levels rather than over 200 and no power is needed once the display is updated. LCD uses about the same power to maintain an image as change it.
An active three layer cell in which each dot can be clear, cyan, magenta and yellow (actually only blocking narrow red, green or blue) would let x3 to x5 more light pass than an RGB filter. RGB has to be side by side to add. CYM needs to be layers to subtract.
Both need the eink white, black and greys for colour or monochrome.
Using an RGB filter:
White = pixels white under R, G and B
Red = Pixels white under R, black under G & B
Orange = Pixels white under R and mid grey under G, black under B.
Yellow = pixels white under R and G
etc...
Pastel shades by changing black to grey and lightning greys.
Tertiary colours can't be as vivid/saturated as the eye can see, or in nature with ANY display device.
All display devices can't do fully saturated R, G and B as brightly as fully saturated Cyan, Yellow and Magenta.
[*It's possible to have an LCD where the black is sort of violet. Other colours are a using external filters. Sadly actual native C, Y and M LCDs don't exist and even if they did there would be parallax issues due to cell thickness]