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Hands on with the Pocketbook Color, Part II

I am still working on my review of Pocketbook’s new ereader, but I thought you might be interested in a follow up post on the screen tech.

The post I published last week sparked a number of requests both here and on MobileRead forums concerning the screen tech. The thing is, E-ink isn’t answering questions about the Kalreido screens, so we knew almost nothing about how it works or what it can do. So when everyone learned that I had a Pocketbook Color, they asked me to test it.

I still don’t really understand how the screenworks, but I was able to confirm that it can display black and grayscale at 300 ppi while simultaneously displaying color at 100 ppi.

I know that sounds improbable, but it’s really what we saw in the photos.

I am going to post the photos below, but first I want to link to the original photos in Google Drive (one, two). My website optimized image files, and that can affect quality. My photos are not of the best quality but I still want you to see the original.

Here’s Pocketbook Color displaying color text:

And here it is displaying shades of gray.

If you zoom in on the images to around 400%, you will notice that the black text and the gray text is displayed using considerably more pixels than the color text. It is quite clear that one is being shown at 300 ppi, and the other is not.

And what is especially interesting is that both the black and the color text are being displayed on the same screen at the same time, only at different resolutions.

I wish I could tell you more about how that was done, but I can’t.

It is cool tech, though, isn’t it?

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davidw August 6, 2020 um 8:31 am

I think this screen works like lcd screens do. That is to say that each pixel has a red subpixel, a green subpixel and a blue subpixel. That way each pixel can assume a color based on an rgb triplet like 256, 0, 0 would be 100% red for 8 bit color.

So to do just black and white you can use all subpixels and not just all pixels which triples the pixel density. And that explains why color is 100 ppi and grayscale is 300 ppi.

vicente August 9, 2020 um 11:27 am

Excuse my impatience, but, when are you going to post your review? Will it be a video review too?

Nate Hoffelder August 9, 2020 um 12:35 pm

I am going to expand the first hands on post into a review momentarily.

vicente August 17, 2020 um 11:02 am

We are still waiting for it 😉

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