Quote:
Originally Posted by ottischwenk
Thanks, the pictures proof that with the same brightness of the screen background, there is a clear difference in contrast in favor of the Kaleido 3 screen (Carta vs Carta 1200) - "black" is darker.
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No, there isn't. Darker or filtered is only more contrast for displays that produce light in or behind the panel (CRT, Plasma, OLED, LCD, VFD, EL etc). This is because the additional filter reduces daylight/external light twice but display light once.
The front light for any eink colour (Triton, Kaleido) is above the colour filter. The colour filter reduces contrast or if perfect would leave it the same. Thus, daylight or front light are both reduced twice and thus the filter layer just makes everything darker. Since the black isn't perfect black, if you increase the light (daylight or frontlight) to the same brightness of white as the mono screen, at best the contrast is identical. However the filter layer has some reflectance so the contrast of ANY coloured eink by R G B pattern of any kind is reduced compared to the same panel in mono due to extra light reflected from the filter.
That's why the official contrast for a Carta1200 mono screen is higher than for a kaleido 3. Also the capacitive touch has reflectance and attenuation, so IR touch with no front light and same incident light will be brighter and slightly higher contrast for the same panel technology. Integrating the capacitive touch on the panel (a recent eink option) mitigates this slightly.
A Gallery colour electronic paper has no filter as it's C M Y cells and thus can in theory have better contrast (but I don't know what it is), but is up to 1.5 seconds to refresh. It's for adverts and signs.