So according to the "deep guide" video review, this uses E Ink's "Gallery 3" e-paper screen. Which, unlike conventional displays, doesn't use additive subpixel color mixing.
Instead it uses subtractive color mixing inside each pixel: It layers transparent cyan, magenta and yellow, and opaque white pigments, over each other. Which creates cyan, magenta, yellow and white as primary colors, and red, green, blue and black as secondary colors. Other shades are then created via dithering those eight base colors. So it works very similar to an inkjet printer.
Since it doesn't use subpixels, the screen seems to have a similar brightness to greyscale E Ink displays, which is reasonably close to printed paper. However, the color saturation is clearly still not quite on the level of actual printed paper.
And of course the reaction times are not as fast as LCD/OLED. As is well known, E Ink uses electrophoresis e-paper screens, where solid electrically charged pigments are moved around in a liquid, which is a slow process. It also still requires a "deghosting" refresh once the screen changes, but interestingly those refreshs are now only applied to the parts of the screen which actually have changed pixel values, which looks significantly less distracting in my opinion.
Japan Display Inc showcased e-paper like LCD 11 years ago. It even has e-paper features like retained pixel at low power consumption. With further work notetaking will be possible. https://www.youtube.com/watch?app=desktop&v=mdXu9jmTI2A
Some 10 to 15 years ago many companies worked on reflective screens, but most all seem to have been abandoned following the dominance of E Ink's monochrome electrophoresis displays.
This makes you wonder if they are hitting some sort of physical limit regarding e-ink technology and color representation. If they are forced to dither them like they are doing now, will we ever get good saturation with e-ink?
Instead it uses subtractive color mixing inside each pixel: It layers transparent cyan, magenta and yellow, and opaque white pigments, over each other. Which creates cyan, magenta, yellow and white as primary colors, and red, green, blue and black as secondary colors. Other shades are then created via dithering those eight base colors. So it works very similar to an inkjet printer.
Since it doesn't use subpixels, the screen seems to have a similar brightness to greyscale E Ink displays, which is reasonably close to printed paper. However, the color saturation is clearly still not quite on the level of actual printed paper.
Here is a comparison shot between Gallery 3 and Kaleido 3 (the latter uses conventional subpixels to create colors): https://assets.goodereader.com/blog/uploads/images/2023/03/2...
And of course the reaction times are not as fast as LCD/OLED. As is well known, E Ink uses electrophoresis e-paper screens, where solid electrically charged pigments are moved around in a liquid, which is a slow process. It also still requires a "deghosting" refresh once the screen changes, but interestingly those refreshs are now only applied to the parts of the screen which actually have changed pixel values, which looks significantly less distracting in my opinion.