New Color Libra and Clara now advertised in US

[khalleron]

Originally Posted by Quoth

Who are "they"?

You can't get the 300 dpi. It's gone because of the printed colour dots.

You keep arguing that, but you are just wrong. Text is 300 dpi, color is 150.

That's the specs. You're drawing conclusions without any evidence.

[Barty]

Originally Posted by Claude_C

They, Kaleido, Kobo, etc.

Why put a 300 dpi panel if you can only get 150 dpi? This makes no sense.

Marketing?

But yes I know what you mean. From eink's website: "Kaleido 3 features a black and white resolution of 300ppi, and a color resolution of 150ppi." This leads people to think that somehow with b&w text you are getting 300dpi.

I'm inclined to believe Quoth this is incorrect. After all the color layer is there whether there is any color on the screen, just as the light layer is there whether you use the light or not.

But then, why mention black and white resolution at all? Do they mean that if you use the kaleido screen without the color capability, you get 300dpi? But then what's the point? That's called a carta screen.

I'm holding out a tiny possibility that something else is going on here, that you do get higher res with grayscale, but I don't know how that would work. Somebody would have to look at the monochrome and colored areas of the screen under a microscope and see if there's any difference

[deleted2]

Originally Posted by Aleron Ives

If they advertised that the colour filter compromises the greyscale performance on regular books, people would be less excited by Kaleido's flawed technology.

Do you have a Kaleido 3 device?

[deleted2]

Originally Posted by Barty

Marketing?

But yes I know what you mean. From eink's website: "Kaleido 3 features a black and white resolution of 300ppi, and a color resolution of 150ppi." This leads people to think that somehow with b&w text you are getting 300dpi.

I'm inclined to believe Quoth this is incorrect. After all the color layer is there whether there is any color on the screen, just as the light layer is there whether you use the light or not.

But then, why mention black and white resolution at all? Do they mean that if you use the kaleido screen without the color capability, you get 300dpi? But then what's the point? That's called a carta screen.

I'm holding out a tiny possibility that something else is going on here, that you do get higher res with grayscale, but I don't know how that would work. Somebody would have to look at the monochrome and colored areas of the screen under a microscope and see if there's any difference

Nothing I’ve seen so far can make me think that we get 150 ppi with black and white text. One guy’s theory vs many great pictures and good videos, plus facts written on companies website. It’s starting to make a lot, don’t you think? But who knows.

[cellaris]

Originally Posted by Claude_C

Just wanting to see the books covers in colours, and some of the pictures that might be in it, or to highlight text in colours, is it enough to lose one's mind?

This could be a good summary to avoid a lot of useless discussions:

https://www.reddit.com/r/kobo/commen...ions/?sort=old

[deleted2]

Originally Posted by cellaris

This could be a good summary to avoid a lot of useless discussions:

https://www.reddit.com/r/kobo/commen...ions/?sort=old

Totally.

[lensmann]

Originally Posted by Quoth

You can't get the 300 dpi. It's gone because of the printed colour dots.

I'm a bit puzzled by this. Kobo's specifications say:

Display
7" E Ink Kaleido™ 3 display with FastGLR and Dark Mode
1264x1680
300 PPI—black-and-white content
150 PPI—colour content

In the EU, that means they have to deliver a product which displays black-and-white content at 300 PPI. Section 18(1)(d) of the Consumer Rights Act 2022 says:

The goods delivered under a sales contract must shall--
(d) be of the quantity and possess the qualities and other features (including in relation to durability, functionality, compatibility and security) normal for goods of the same type that the consumer may reasonably expect given the nature of the goods and taking into account any public statement in relation to the goods made by, or on behalf of, the trader or any other person constituting a previous link in the chain of transactions relating to the sales contract, including the producer, particularly in advertising or on labelling. (emphasis added)

That's an Irish law, but it's based on EU directives and all EU countries will have similar provisions (as will the UK). It makes it quite clear that if a product is advertised as having 300 PPI, then the delivered product must have that functionality. It surely can't be that Kobo is acting in flagrant disregard of this law. There must be some sense in which the screen does in fact display black-and-white content at 300 PPI.

[Aleron Ives]

I think the idea is that since the colour film is on top, it's blocking the 300 PPI monochromatic screen below, so when you view greyscale content, the colour film is still there, obscuring the screen underneath slightly compared to a non-Kaleido 300 PPI screen. The main thing you'll notice is the reduced contrast, but I suppose the clarity might take a hit, too.

[cellaris]

I have witnessed exhausting discussions on this and other forums about the contrast and resolution of Kaleido 3. And the only thing I have learned is that it is best to trust your own eyes.

I have a hard time finding any difference in the black text on my eReaders with the Carta 1200 screen (Paperwhite 5; Tolino Vision 6, which has the same screen as the Kobo Libra 2; PocketBook Era, and Leaf 2) when I put them next to the Tab Mini C. I've compared them countless times and the differences are very small, nuanced differences. By contrast, when I compare the Tab Mini C's colour text with the black text of my monochrome readers (or with those of the Tab Mini C itself) the difference is immediately apparent. Not that I want to contradict physics and logical reasoning, but my eyes tell me otherwise. And I read with my eyes. (I could quote several reviews from people I trust who have been in the world of e-readers for many years and who perceive it as I do, but it is not worth it. Everyone has to convince himself).

The first time I held a colour e-reader in my hands I noticed that it looked different, not because of the contrast and resolution, but because of the grainy background. It's hardly noticeable, but if you look closely you can see it. And I was about to return it because of that. But after an hour I got used to it and it stopped being a problem for me. In the early days I always had a second (monochrome) e-reader with me next to my colour e-reader because I was not sure if it would look good or not. Sometimes I swapped it to see if I noticed a big difference, but finally I decided it wasn't necessary. And for many months now, the Tab Mini C has been my primary e-reader for any kind of content and I prefer it to any of my other monochrome e-readers. What interest or need do I have in reading on an e-reader that supposedly looks bad, when I have such good e-readers? It's not that I'm a masochist and want to read in worse conditions, it's simply that I like it better.

But this is just my personal experience and does not necessarily coincide with that of others. I have read people complaining about the contrast and that they have seen blurred text and immediately returned their colour e-readers. And I have also read opinions very similar to mine. Who is right? Trust your own eyes, not the opinions of others (let alone those who haven't even had direct experience).

[JSWolf]

What I really would like to see is the Libra 2 compared to the Libra Color with normal light and no front light on.

[Quoth]

Originally Posted by JSWolf

What I really would like to see is the Libra 2 compared to the Libra Color with normal light and no front light on.

Yes.
In closeup at same distance, with camera white balance, exposure etc locked. Not a video or phone photo.

[Quoth]

Originally Posted by lensmann

I'm a bit puzzled by this. Kobo's specifications say:


In the EU, that means they have to deliver a product which displays black-and-white content at 300 PPI. Section 18(1)(d) of the Consumer Rights Act 2022 says:



That's an Irish law, but it's based on EU directives and all EU countries will have similar provisions (as will the UK). It makes it quite clear that if a product is advertised as having 300 PPI, then the delivered product must have that functionality. It surely can't be that Kobo is acting in flagrant disregard of this law. There must be some sense in which the screen does in fact display black-and-white content at 300 PPI.

The 300 dpi has been put in by marketing people. They will get in trouble, but only when people complain. It's not proactive.

Various TV and panel makers and MS did cause controversy over claims for PenTile displays and subpixel addressing such as Cleartype.
https://en.wikipedia.org/wiki/PenTile_matrix_family

With the increasing availability of HiDPI displays after 2012, subpixel rendering has become less necessary
https://en.wikipedia.org/wiki/ClearType

Originally all colour systems used either stripes or a wheel/drum. But beam indexed stripes in 1950s was a problem and the single gun CRT wasn't viable till the 1990s, but then made obsolte by Plasma and LCD. So in 1952 till Trititron the triad of dots and a shadowmask used.

Stripes came back with LCDs, but in the last 20 years many sub pixel layouts tried. ALL LCD planels, like mono eink are mono and higher resolution than the resulting display.
See
https://en.wikipedia.org/wiki/Pixel_geometry
Only has some options. Triton eink was R G B stripes, so a 300 dpi panel would give 100 dpi x 300 dpi.
The Kaleido is a pattern of pastel red, green and blue in a 2 x 2 layout. Pastel to improve brightness, so the 300 dpi is reduced to 150 dpi colour.

It's true that with a pure mono image or text you get a bit better than 150 dpi, but not a real 300 dpi. You can't switch off the printed colour dots.
Electronic cameras used to use either three sensors or stripes, then they changed to approximately a 2 x 2 cell.
See https://en.wikipedia.org/wiki/Bayer_filter
If the sensor is 4000 x 3000 then the full colour resolution is 2000 x 1500 square pixels, unlike stripes which would be 4000 x 1000 or 1333 x 1500.
Any display filter works for a camera, and any camera filter works for a display, except the sensor is processed by software/HW and the display is "processed" by your eyes.
I don't know what exact layout Kaleido is, but since they quote 150 dpi colour for a 300 dpi panel, it's the rectangular (less than ideal) Bayer layout if the panel is the regular mono type. If they can offset each row of pixels alternately by 1/2 pixel (unlikely) then they can use the better delta layout:
https://en.wikipedia.org/wiki/Pixel_geometry

See also

The second common method uses a typical grey scale e paper display behind a transparent color layer. The color layer is a LCD based CFA. When displaying grey scale images the device runs at its native resolution, for instance, 300 pixels per inch (PPI). However, due to the CFA, the resolution of the device drops when displaying color images, say to 100 PPI.[35] When the image to be displayed consists of both a colored and a black and white section, for example when a book page comprises plain text as well as a color photo, some e book devices may display the photo at the reduced resolution while the text is at the normal resolution. As the CFA is LCD based, the CFA requires constant power to run and uses more energy.

This is actually WRONG! The 300 dpi is lost due to the colour filter. The article also seems to suggest Triton (100 dpi, which is still 300 dpi on the other axis).
https://en.wikipedia.org/wiki/Color_...ay#E-paper_CFA
Also it's a CFA the same as used on an LCD. There is no LCD layer on any eink panel.

Kobo will be fine in the EU until someone brings a complaint.

It's true that black text on "white" paper will be better than a native 150 dpi panel like on DXG or other 9.7″ ereaders, but can't ever be as sharp as a 300 dpi mono panel without a printed colour pattern.

As with HiDPI displays, at a certain point a colour panel less than 300 dpi will look as good as mono 300 dpi, probably about 225 dpi, which would need a mono panel of about 450 dpi.

If you'd benefit from reading glasses and don't use them then the Libra Colour will look as good as the Libra2. But it's misleading to claim that a 300 dpi mono image/text on the Libra Colour is as sharp as the 300 dpi Libra 2. It's physically impossible.

[Quoth]

I hate to be a damp squib, but there is another issue with treating a 300 dpi mono panel with a 2 x 2 pattern of printed dots matched up to the pixels to give 150 dpi colour as if it's just a mono panel with 300 dpi mono content?

What happens with small fine fonts with 300 dpi 1 pixel wide strokes? You get false colour.

What happens with patterned 300 dpi detail in mono, or a mono image with dithering? You can get fine lines, patterns and patches of a particular colour.

Because the CFA= printed pattern at 300 dpi of pastel shade red, green and blue translucent dots. It can't be turned off.

On cameras they solve this by an optical filter that blurs fine detail to the resolution of the total pixels for colour.

On displays driven by gpus they anti-alias any image detail higher than the display resolution for images. Text may deliberately use sub-pixel addressing.

So to avoid colour artefacts on a Kaleido panel the display controller should not treat the panel as 1680x1264 in mono (300 dpi), but anti-alias it down to 840 x 632 colour (150 dpi) in some manner.

Potentially a skinny font in dark mode at 300 dpi would have green, or red, or blue strokes. Font generation/rendering of thin/small fonts would need to be aware of the 2 x 2 layout of printed coloured dots, then finer detail than 150 dpi can be achieved.

[Quoth]

The micro textured surface* of the ereader screen can be slightly coarser than on the best 300 dpi panels to better blend the coloured pixels to mono (like the anti-aliasing filters on a camera sensor, but then you still don't get 300 dpi mono).


[* Which is why most eink ereaders are less shiny/less glare than most tablets & phones, it's not because they are eink!]

[JSWolf]

Originally Posted by Quoth

Yes.
In closeup at same distance, with camera white balance, exposure etc locked. Not a video or phone photo.

With a good camera and by someone who knows how to take photos that are clear/sharp and not blurry.

What's wrong with a good video camera?