Still can't decide between an iPad Pro and Onyx Boox Tab X

[Bookchin]

It's been a few years and I'm still in limbo about this. I need a large screen to view academic PDFs, and the choices seem to come down to an iPad Pro or the Tab X.

Several years ago I tried an iPad Pro borrowed from a friend and it was alright for reading but staring into a lit screen was a bit uncomfortable during long periods. When I turned down the brightness to very low, the screen started to flicker slightly. (I don't know if Apple has fixed this issue in later models?)

I've never tried an e-ink screen before so I don't know how I would like it. Actually, I did try briefly doing some reading on a Sony e-reader a long time ago. The visual experience was what I recall as 'machine-like'. Kind of like an etch-a-sketch, with the grey background and dark grey text. I'm sure e-ink has greatly improved since then.

I guess one alternative might be a Samsung 12" tablet with an AMOLED screen. But I've heard AMOLED also flickers at low brightness.

So I guess I'm still in limbo. If I knew my eyes would be ok with an iPad Pro or a Samsung tablet, I'd prefer those options, if only because they are more versatile and can be used for so many other purposes (especially ones that require color).

[kekinash]

My iPad Pro 11 from 2021 doesn’t flick. I rather prefer it for pdf reading due the color screen and being more powerful and responsive dealing with complex pdfs. E-ink for me is only to read some books, but not all books. Those with graphics and colored text are best viewed in a regular tablet.

[kandwo]

I briefly tried the Max Lumi and the low contrast in combination with the low resolution (207 PPI) just made it impossible to use. The text was blurry and made my eyes water, trying to focus on it.

Later generations should have better contrast. Lumi 2 added Carta 1250 and Tab X further tries to improve that with a new thinner glass layer. The resolution is still low, though.

It's rumored that Onyx Boox will release a 13" Kaleido 3 tablet next year. And from what I've heard the PPI should be slightly better for 13" on Kaleido 3. On E-ink's own website they only mention 300 PPI for Kaleido 3, but I doubt it'll improve that much: https://www.eink.com/brand/detail/Kaleido3. But if that holds true also for 13" like their webpage makes it sound - that'd be your answer.

If you need it now you might consider ordering both and returning one of them.

[Quoth]

The real resolution for Kaleido 3 is 150 dpi for colour (if it's based on a 300 dpi panel), and the illusion of better with high contrast monochrome, because the 300 dpi of the panel is lost forever when you have a colour filter pattern on it.
Similarly you can't call a colour LCD by the mono resolution of the LCD without the filter.
It's misleading marketing to claim Kaleido 3 panels have the resolution of the original mono eink.
Yes, the mono text can use sub-pixel addressing, but that does not make it back into a 300 dpi panel for monochrome.

[mobama]

When in doubt, buy both.

[Bookchin]

Originally Posted by kekinash

My iPad Pro 11 from 2021 doesn’t flick. I rather prefer it for pdf reading due the color screen and being more powerful and responsive dealing with complex pdfs. E-ink for me is only to read some books, but not all books. Those with graphics and colored text are best viewed in a regular tablet.

It doesn't flicker even at very low brightness?

[Quoth]

I've no phones or tablets that flicker at low brightness.

[JSWolf]

Originally Posted by Quoth

The real resolution for Kaleido 3 is 150 dpi for colour (if it's based on a 300 dpi panel), and the illusion of better with high contrast monochrome, because the 300 dpi of the panel is lost forever when you have a colour filter pattern on it.
Similarly you can't call a colour LCD by the mono resolution of the LCD without the filter.
It's misleading marketing to claim Kaleido 3 panels have the resolution of the original mono eink.
Yes, the mono text can use sub-pixel addressing, but that does not make it back into a 300 dpi panel for monochrome.

Because of the Kaleido panel, when reading in mono, the screen is a lot darker then it would be without the Kaleido panel.

[cellaris]

Originally Posted by Quoth

It's misleading marketing to claim Kaleido 3 panels have the resolution of the original mono eink.
Yes, the mono text can use sub-pixel addressing, but that does not make it back into a 300 dpi panel for monochrome.

So what would be the real resolution, in your experience?

[Quoth]

Originally Posted by cellaris

So what would be the real resolution, in your experience?

It's physics.

Well done sub pixel addressing gives better visual appearance than the colour resolution, but depends on content, but it can never get back the original resolution.

An older stripe filter (R G B) loses resolution in horizontal direction but has full resolution vertically. Because you are more sensitive to green than red or blue the sub-pixel addressing putting blue and red edges on the white surrounding black text makes the text much better.

The newer LCD (inherently mono like eink) and OLED and Kaleido 3 use a 2 x 2 patten. This means instead of 100dpi x 300 dpi for a 300 dpi panel, you have 150dpi x 150dpi, so colour resolution is better overall. However the sub pixel addressing for black text on white now isn't so advantageous. The perceived mono text quality will vary by viewer's eyesight and font. It's a scheme that suits coloured images best. But the underlying panel for eink does black and white, and only just manages 14 grey levels. Also the Kaleido is less dense and less saturated compared to Triton (conventional stripes like older LCDs) so as to make it brighter and better contrast. This desaturates the colours giving a washed out or pastel-look to the colour images, but slightly improved black text. It's simply dishonest to claim any colour panel technology using a mono panel has the original resolution in mono.
If it was true tt would be just as valid for 2 x 2 cell LCD (or QLED which is actually mono LCD, blue backlight and red + green quantum dots that's 1920 x 1080 colour to make the claim that those are 4K (3840 x 2160) in mono. They are not. Some use the same layout of R, G and B filtering as Kaleido. The dishonest claims for mono are only standing because it's a niche product with essentially a monopoly. It certainly can't compete with LCD, OLED, LED, QLED etc on colours/shades/hues (less than 4096 vs millions) or response time, or pixel addressing or contrast or greys (14 vs 254 to 1022).
If Kaleido 3 was on any mainstream product the claim that it's 300 dpi for mono would be axed. It's not physically or mathematically possible as soon as you have a colour filter of ANY kind of density and layout. Unless of course they had a 600 dpi mono panel under the filter.

This writes

It takes advantage of the fact that each pixel on a color liquid-crystal display (LCD) or similar is composed of individual red, green, and blue components — subpixels

That "or similar" applies also to eink (but not Gallery ACEP), QLED (really LCD) and in theory to OLED and actual LED panels too.
https://en.wikipedia.org/wiki/Subpixel_rendering

The Gallery 3 panel* really has exactly same resolution for mono and colour, as does colour wheel DLP and three chip DLP projectors and colour cameras using three sensors and a splitter. Using the sub pixel addressing won't achieve the full resolution mono would have that same number of pixels if they were not R, G and B.

[* But ACEP / Gallery 3 is staggeringly slow at 1.5 s (1500 ms) for a full refresh and still worse rendition than LCD]

However at higher dpi usually sub-pixel addressing isn't used, so even apparent mono resolution = colour resolution. Grey anti-aliasing looks better above a certain resolution depending on viewing distance, and none at higher still. My desktop screen has a real colour dpi of just over 200 dpi, so I have it set to Grayscale instead of Subpixel smoothing.

Certainly if the eink panel was inherently 400dpi you'd not do any subpixel addressing. You'd have 200 dpi mono or colour, no matter image type or dark mode.

But at normal reading distance with correct reading glasses the 150 dpi is noticeably poor (Kindle DXG or other LCD screens I have).

[cellaris]

Originally Posted by Quoth

It's physics.

Well done sub pixel addressing gives better visual appearance than the colour resolution, but depends on content, but it can never get back the original resolution.

An older stripe filter (R G B) loses resolution in horizontal direction but has full resolution vertically. Because you are more sensitive to green than red or blue the sub-pixel addressing putting blue and red edges on the white surrounding black text makes the text much better.

The newer LCD (inherently mono like eink) and OLED and Kaleido 3 use a 2 x 2 patten. This means instead of 100dpi x 300 dpi for a 300 dpi panel, you have 150dpi x 150dpi, so colour resolution is better overall. However the sub pixel addressing for black text on white now isn't so advantageous. The perceived mono text quality will vary by viewer's eyesight and font. It's a scheme that suits coloured images best. But the underlying panel for eink does black and white, and only just manages 14 grey levels. Also the Kaleido is less dense and less saturated compared to Triton (conventional stripes like older LCDs) so as to make it brighter and better contrast. This desaturates the colours giving a washed out or pastel-look to the colour images, but slightly improved black text. It's simply dishonest to claim any colour panel technology using a mono panel has the original resolution in mono.
If it was true tt would be just as valid for 2 x 2 cell LCD (or QLED which is actually mono LCD, blue backlight and red + green quantum dots that's 1920 x 1080 colour to make the claim that those are 4K (3840 x 2160) in mono. They are not. Some use the same layout of R, G and B filtering as Kaleido. The dishonest claims for mono are only standing because it's a niche product with essentially a monopoly. It certainly can't compete with LCD, OLED, LED, QLED etc on colours/shades/hues (less than 4096 vs millions) or response time, or pixel addressing or contrast or greys (14 vs 254 to 1022).
If Kaleido 3 was on any mainstream product the claim that it's 300 dpi for mono would be axed. It's not physically or mathematically possible as soon as you have a colour filter of ANY kind of density and layout. Unless of course they had a 600 dpi mono panel under the filter.

This writes

That "or similar" applies also to eink (but not Gallery ACEP), QLED (really LCD) and in theory to OLED and actual LED panels too.
https://en.wikipedia.org/wiki/Subpixel_rendering

The Gallery 3 panel* really has exactly same resolution for mono and colour, as does colour wheel DLP and three chip DLP projectors and colour cameras using three sensors and a splitter. Using the sub pixel addressing won't achieve the full resolution mono would have that same number of pixels if they were not R, G and B.

[* But ACEP / Gallery 3 is staggeringly slow at 1.5 s (1500 ms) for a full refresh and still worse rendition than LCD]

However at higher dpi usually sub-pixel addressing isn't used, so even apparent mono resolution = colour resolution. Grey anti-aliasing looks better above a certain resolution depending on viewing distance, and none at higher still. My desktop screen has a real colour dpi of just over 200 dpi, so I have it set to Grayscale instead of Subpixel smoothing.

Certainly if the eink panel was inherently 400dpi you'd not do any subpixel addressing. You'd have 200 dpi mono or colour, no matter image type or dark mode.

But at normal reading distance with correct reading glasses the 150 dpi is noticeably poor (Kindle DXG or other LCD screens I have).

So are we talking about a real resolution of 150 dpi? 200 dpi? The figure is not clear to me.

To put it in terms of current e-readers, do you mean that if I read a normal book (without colour) on an Onyx Boox Tab Ultra C, the text will look the same (or worse) than on a PocketBook InkPad Lite (150 dpi) or on a Meebook P10 (200 dpi)?

[Quoth]

The text will be better than a real mono 150dpi (Kindle DXG, Inkpad Lite) , but never as good as real mono (no colour filter) 300 dpi. How much better than 150 dpi will depend on viewing distance, your eyesight, reading glasses if required, font and what method of sub-pixel addressing they use (if any).

It might look better or worse than a 200dpi P10, depending on viewing distance, your eyesight, reading glasses if required, font and what method of sub-pixel addressing they use (if any). It will look better than a 200 dpi (finest mode) fax because that uses only black or white, no aliasing on curves/diagonals using greys. It might even look better than an ancient 300 dpi laser print, as those had fixed dot size and no greys. Most mono ereader renderers seem to anti-alias diagonals using the 14 grey levels which can make 300 dpi eink mono comparable to 1200 dpi laser text.
See https://en.wikipedia.org/wiki/Spatial_anti-aliasing

Explains how having greys improves the apparent resolution on curves and diagonals. Vertical and horizontal elements are unaffected, so some kinds of images purely in black and white with no greys look just as good on 200 dpi fax as 200 dpi eink and will look better on 300 dpi ancient laser prints. But images with diagonals curves or greys will sometimes look far better on 300 dpi eink than a 600 dpi laser. Some inkjets and lasers can vary dot size so as to get more shades on a denser dither.


See also https://en.wikipedia.org/wiki/Font_rasterization


Somewhere I have books I used as references to write graphics drivers for games during 1992-1996. Early 3D games actually used purely 2D techniques. It's a very complex subject and most of the related patents are just gaming the USPTO because the techniques known decades earlier. Of course for older games you pre-rasterised the fonts needed for the resolutions needed to save CPU and space. Sub-pixel addressing was known but not used as it doesn't work on CRTs (monitors or TVs). Any LCDs were rare, low resolution and mono in 1980s.

[cellaris]

Will the difference in resolution between colour text (not an image) and black text be noticeable or very similar?

(I am not trying to get anywhere with these questions. I have monochrome e-readers with the different resolutions that have been discussed and I have an e-reader with a Kaleido 3 screen, and I have compared them with each other and already have an opinion of my own as to which one looks better or worse, but I want to understand your approach and your answers help me by confronting them with my personal experience).

[ottischwenk]

Originally Posted by Quoth

The text will be better than a real mono 150dpi (Kindle DXG, Inkpad Lite) , but never as good as real mono (no colour filter) 300 dpi. How much better than 150 dpi will depend on viewing distance, your eyesight, reading glasses if required, font and what method of sub-pixel addressing they use (if any).

You obviously still haven't figured it out - it's so simple!
In any case, black is displayed in 300 ppi - there is no other way.
and the adjacent 300 ppi color pixels are too small to be seen individually without a magnifying glass.

[Quoth]

Originally Posted by ottischwenk

You obviously still haven't figured it out - it's so simple!
In any case, black is displayed in 300 ppi - there is no other way.
and the adjacent 300 ppi color pixels are too small to be seen individually without a magnifying glass.

It's not 300dpi just because you can do black at 300 dpi with coloured edges. Do read how subpixel addressing works and how anti-aliasing works. Despite your confusion a 300dpi panel with colour filter on it for 150 dpi colour can never equal a mono panel with no filter even with mono content.

You are simply describing sub-pixel addressing.

You are misleading people. I've explained carefully why with mono content it can look better than 150 dpi, but can never equal a 300 dpi panel with no filter on it.

Also for decent eyesight or proper reading glasses the consensus is that you need 200 dpi colour minimum. Then you don't need sub-pixel addressing and can use regular anti-aliasing. I've texted many LCD panel resolutions and it's the same principle, a mono panel with a colour filter. A 150 dpi colour isn't good enough. If you want to read novels you'd want a 200 dpi colour panel, i.e, if 2 x 2 cell, a 400 dpi mono under the filter.
This is out of date as it only has stripe filters, not 2 x 2, but the explanations and conclusions are still true.
https://www.smashingmagazine.com/200...anti-aliasing/

Differences and similarities of eink colour (Triton or Kaleido, not Gallery) and LCD:
Both use a mono panel with a colour filter. The exact same design of filter could be used, but Kaleido uses less pure colours to improve brightness.
There can be stripe, 2 x 2 and pentile layouts.
The eink only has 14 grey levels, black and white. The LCD has 254 (standard) to over 1000 levels (HDR).
Black on both is opaque. White on LCD is clear pixels. Reflective (eink) vs Transmissive (lcd).
There is no difference to black resolution on eink colour (Triton or Kaleido, not Gallery) and any other colour panel using sub-pixels of primary colour. No-one claims an HD colour LCD is 4K for black, but it does black at same resolution as an HD Kaleido display.

Sub-pixel addressing on a 2 x 2 colour matrix 150 dpi can create an appearance of 300 dpi, but it's nothing like as good as a native 300 dpi mono and how good it an illusion it is depends on the viewer. The "improved" quality is controversial, which is why at 200 dpi and higher colour it's normally not used.
No-one claims a colour LCD has it's native resolution with monochrome text, because it would be a lie. The same applies to Kaleido or Triton eink.