600 ppi this year or next? Good ereader speculates

[HLS]

I think the 300 PPI we have is just fine. Looks great and paperback like to me. I do not see a need for higher pixels unless its a color ereader. I feel ereaders now are too expensive as it is

[fjtorres]

Originally Posted by GeoffR

I am a human and I can easily see the quality difference between 600dpi and 1200dpi with laser printed text, so the idea that the human eye cannot tell the difference is simply nonsense.

(Edit: That's not to say it is a particularly important difference, there are other things that are much more important for reading than high dpi, such as using a well-designed font, good typesetting, fine-tuning layout to suit personal preferences, etc. )

Laser printers are purely b&w and produce shading by halftone dithering.
Eink displays are grayscale. 16 shades most commonly.
For a laser printer to produce 300dpi/16 shades like today's eink it would need to go to 1200dpi.

https://superuser.com/questions/8497...lack-and-white

A 600dpi grayscale eink display would be comparable to commercial offset lithographic pbooks. Pretty clearly overkill and not worth the higher cost required.

[Apache]

Originally Posted by fjtorres

Laser printers are purely b&w and produce shading by halftone dithering.

There are color laser printers.
Apache

[fjtorres]

Originally Posted by Apache

There are color laser printers.
Apache

There aren't any real color eink devices, though, and that was the baseline for comparison, no? Yes, some fake color with filters but they're really monochrome devices underneath.

The same is true of laser printers: they're monochrome devices that use 3 or 4 colors of toner and dither to produce the images. The result is closer to 150-200dpi images than true 600 dpi. Much less true photographic imagery.

https://computer.howstuffworks.com/laser-printer11.htm

True (photographic quality) high res color printing requires mixing the pigments to generate a true shaded pixel rather than a dithered or overlaid cluster of different colors. High end inkjets and dye diffusion printers are the best way to get true color pallets in the 16-bit to 24-bit range. Lasers are adequate for consumer use but way behind in actual quality for professional use.

https://en.m.wikipedia.org/wiki/Dye-sublimation_printer

https://www.ldproducts.com/blog/pros...aser-printers/

The good news is that at reading distances most people can't really resolve images beyond 150 dpi.

https://www.quora.com/What-is-the-re...-in-megapixels

[ilovejedd]

Originally Posted by fjtorres

The good news is that at reading distances most people can't really resolve images beyond 150 dpi.

https://www.quora.com/What-is-the-re...-in-megapixels

Note, the 150 dpi mentioned is for photos. Text and line art, there's a noticeable difference between 150 and 300 dpi.

I can actually read manga on my smartphone's 5.2" 1080p display. Not particularly comfortable but it is legible. Meanwhile, the same manga required zooming on a 9.7" 1024*768 iPad 2 despite the iPad's much larger display size.

That said, yeah, 600 ppi sounds like overkill. The reader would need a much faster processor, too, adding to the power consumption.

[rkomar]

Originally Posted by ilovejedd

Curious though wouldn't higher pixel density help with contrast?

I think it's possible that higher pixel density would lead to worse contrast, given E-Ink technology. The ink particles are contained within some kind of transparent globes. The pixel density partly depends on how small you can make the globes. If you can't reduce the thickness of the globe material when shrinking the size, then more space gets taken up by that, relatively speaking. Smaller globes also mean a thinner layer of ink particles, which might affect the contrast. This is all guesswork on my part, but it makes sense to me.

[fjtorres]

Originally Posted by rkomar

I think it's possible that higher pixel density would lead to worse contrast, given E-Ink technology. The ink particles are contained within some kind of transparent globes. The pixel density partly depends on how small you can make the globes. If you can't reduce the thickness of the globe material when shrinking the size, then more space gets taken up by that, relatively speaking. Smaller globes also mean a thinner layer of ink particles, which might affect the contrast. This is all guesswork on my part, but it makes sense to me.

Here, too.
Eink contrast ratio is pretty much maxed out.
Part of the problem is the globe material: it covers both the black side and the "white" side so it makes the dark side lighter and the light side darker. Front lighting helps a bit. Backlighting would help more but at that point you might as well go LCD.

The way display technology is evolving I think microLEDS will take over whatever dedicated reader market remains starting around the middle of next decade.

https://www.androidauthority.com/mic...lained-805148/

[Dr. Drib]

I look forward to it.

After all, that means the pinholes [manufacturing defects] will be twice as small, making the light leakage much less.

[j.p.s]

I doubt that microLED will be cost competitive with OLED in 6 years at 5" to 13" display sizes.

[rkomar]

Originally Posted by fjtorres

Part of the problem is the globe material: it covers both the black side and the "white" side so it makes the dark side lighter and the light side darker. Front lighting helps a bit.

It also leaves a greyish space around the globe contents that always stays the same colour. So, it washes out the blacks and whites that way, as well.

[tomsem]

Originally Posted by DNSB

Hmmm... I suspect you would not be happy for that long. OLED does use quite a bit more power than eInk.

It would not be an issue for me.

iPhone XS (for example) supports 14 hours of video playback (presumably with wireless off). This would just be reading, and for me, using black theme, the black pixels (x000000) do not draw energy as there is no backlight. I have to work, sleep, eat, even talk to other people etc. There are plenty of opportunities to top off the battery, and you can use fast chargers as well.

If it were a dedicated reading device, no need to play video games etc., you would not need a high performance CPU or other components and could manage wireless energy more aggressively. A 6-inch, say 360 dpi OLED screen would probably still make it cost more than an Oasis but with great color and great contrast...but it won’t happen unless OLED gets dramatically cheaper to manufacture. And probably even I wouldn’t buy one.

[GeoffR]

Originally Posted by GeoffR

I am a human and I can easily see the quality difference between 600dpi and 1200dpi with laser printed text, so the idea that the human eye cannot tell the difference is simply nonsense.

Originally Posted by fjtorres

Laser printers are purely b&w and produce shading by halftone dithering.
Eink displays are grayscale. 16 shades most commonly.
For a laser printer to produce 300dpi/16 shades like today's eink it would need to go to 1200dpi.

Note that I was talking about text, not shaded images.

Shading in text is only needed for anti-aliasing, which trades off sharpness for smoothness. So a 300dpi greyscale text cannot match the smoothness of 600dpi black-and-white text without a loss of sharpness..

[GeoffR]

Originally Posted by ilovejedd

That said, yeah, 600 ppi sounds like overkill. The reader would need a much faster processor, too, adding to the power consumption.

Increasing the dpi without changing the greyscale level would probably need more memory and processor power, but if they increased the dpi and reduced the greyscale level that could increase the display quality of text without increasing the memory required, and maybe even reduce the processor power needed.

Extra processor power is needed to do things like anti-aliasing of text and font hinting, but at higher dpi levels these things are not needed so much, and if the dpi is high enough they are not needed at all.

Also, increased dpi, even with a reduced greyscale level, could allow some readers to use a smaller font size or a more compact font-face which means more words on the page and so fewer page turns, reducing power consumption on e-ink devices.

[DNSB]

Originally Posted by fjtorres

Here, too.
Eink contrast ratio is pretty much maxed out.
Part of the problem is the globe material: it covers both the black side and the "white" side so it makes the dark side lighter and the light side darker. Front lighting helps a bit. Backlighting would help more but at that point you might as well go LCD.

Umm... an eInk display works by moving the white or black particles to the viewing surface of the capsule. A backlight would have to try shining through the entire sandwich and would not work at all never mind help more.

[DNSB]

Originally Posted by tomsem

It would not be an issue for me.

iPhone XS (for example) supports 14 hours of video playback (presumably with wireless off). This would just be reading, and for me, using black theme, the black pixels (x000000) do not draw energy as there is no backlight. I have to work, sleep, eat, even talk to other people etc. There are plenty of opportunities to top off the battery, and you can use fast chargers as well.

If it were a dedicated reading device, no need to play video games etc., you would not need a high performance CPU or other components and could manage wireless energy more aggressively. A 6-inch, say 360 dpi OLED screen would probably still make it cost more than an Oasis but with great color and great contrast...but it won’t happen unless OLED gets dramatically cheaper to manufacture. And probably even I wouldn’t buy one.

Increasing the battery of an ereader to match the battery size of an iPhone XS would also increase the weight of the ereader. As for adding fast charging, wireless charging, etc., these are going to increase the weight and expense past the point where I suspect most users would be happy with it.

I do have to agree that the cost of the OLED display would have to drop very dramatically to make it cost effective. The last time I was looking at a project that used a 6" display, the OLED display option added $280US to the cost with the base LCD/LED backlight screen.