My Oasis has splotchier lighting than any early Paperwhite or Voyage I've seen.

[kobayashi]

Originally Posted by howyoudoin

I am concerned for HarryT's eyesight.

+1

Originally Posted by badgoodDeb

Some of us are also aware that physics dictates that the area closest to the light source is brightest, and so our mind just equalizes the color. When I sit in a chair beside a lamp, and read a paper book, there is gradation of brightness across each page, and in the valley of the spine. So I expect the same gradation across all physical objects.

That said, I would make a lousy painter, because I don't often notice the many different shades of green within one tree. The differences that are due to physics, lighting, etc: my mind wipes those away, and tells me "yes, this is a three dimensional object. Color variations are how I know that. Now you can forget those color variations, because they are normal".

So what some term "more discerning", strikes some of us as "far too picky". It's just semantics. So don't yell as us for not caring, and we'll try not to yell at you for caring, that the color changes a bit across a page. My minds tells me that such slight color changes are normal, because, well, "Physics". So I dismiss it.

None of that is correct unless you're claiming that other e-readers defy the laws of physics because they don't have the massive color gradient that plagues the newest Kindles.

[tomsem]

Certainly the color (or 'prism-ing', where white light is split into its constituent spectra) issues are more obvious when there's not much ambient light, and the light level of the LEDs is low (as in most of the pictures posted here).

My conclusion is that the tolerances involved are too narrow to control perfectly. It is probably the capacitative layer between the glass (or plastic) light guide and the e-ink layer that is responsible for the prism-ing, as it is sprayed on and very thin, so even a small variation in thickness can cause 'special effects'.

Because I'm one of those people who can readily see these imperfections, I gave up on reading my Paperwhite in the dark a long time ago, and vastly prefer reading on my smartphone or tablet in those conditions (using Night theme), and tend to avoid doing much of that type of reading.

For me, it is perfectly fine once there's a minimal amount of ambient light to mix with the front light. I'm not nostalgic for the good old days when I was using clip-on lights and lighted covers.

[AnemicOak]

I think Amazon is the only one doing capacitive touch on their readers with everyone else using IR?

I wonder if the coloring is coming from the transparent conductive layer (I'm guessing they're using Indium tin oxide) of the touch screen in conjunction with the way it's being lit.

[soulfuldog]

Originally Posted by kobayashi

None of that is correct unless you're claiming that other e-readers defy the laws of physics because they don't have the massive color gradient that plagues the newest Kindles.

The colour gradient (which is different to the blotches/shadows/smudges of the original PW, and which Josieb1 has mentioned in relation to her Kobo Glo HD in this thread), appears to only affect the Voyage and the Oasis. The only current ereaders that have a flush, capacitive touch screen.

IIRC, the only other ereader with this type of screen is the Kobo Aura (the older 6" version not the newer Aura HD or H2O), which is a fine ereader, but is the least impressive of the Kobo models because its screen has "issues". Not sure about a colour gradient but its not the clearest and also had weird scratches and a really annoying (for me) shadow line along the top of the screen.

[kobayashi]

The Kobo Aura didn't have the color gradient issues. It had etching in the screen to reduce glare that also reduced sharpness.

[badgoodDeb]

Originally Posted by kobayashi

+

None of that is correct unless you're claiming that other e-readers defy the laws of physics because they don't have the massive color gradient that plagues the newest Kindles.

I'm telling you that my brain explains away little color variations. There is nothing correct or incorrect in that. I just expect little color variations to be normal, so I don't notice it.

Your brain may not be wired the same way. Did I say your brain was "incorrect"??

( Yes, I thought it. But I didn't SAY it! )

[badgoodDeb]

Originally Posted by tomsem

For me, it is perfectly fine once there's a minimal amount of ambient light to mix with the front light. I'm not nostalgic for the good old days when I was using clip-on lights and lighted covers.

Amen to this! I never tolerated clip on lights. So I'm not completely gradient-blind.

[soulfuldog]

Originally Posted by kobayashi

The Kobo Aura didn't have the color gradient issues. It had etching in the screen to reduce glare that also reduced sharpness.

Its just one image, but it just happens to be the first one I found from browsing in the Kobo Aura first impressions thread. Maybe it was a poor example of the Aura, but that screen had similar (and more) issues to my eyes.

https://www.mobileread.com/forums/sho...&postcount=325

[kobayashi]

Originally Posted by soulfuldog

Its just one image, but it just happens to be the first one I found from browsing in the Kobo Aura first impressions thread. Maybe it was a poor example of the Aura, but that screen had similar (and more) issues to my eyes.

https://www.mobileread.com/forums/sho...&postcount=325

You're right about that picture. I hadn't seen one like that before. Like you said before, the Aura had plenty of other screen issues given that it was so ahead of its time with the flush, capacitive screen.

I would have expected the Voyage screen to be better than the Aura (and it is) and the Oasis screen to be better than the Voyage (it is not.)

[David58117]

Originally Posted by kobayashi

The Kobo Aura didn't have the color gradient issues. It had etching in the screen to reduce glare that also reduced sharpness.

God - I had the original Kobo Glo - the etching was a nightmare.

Mine looked like scratches, and was one of those things that drives you crazy once you notice it.

It did have spotlighting too.

[Jason90]

Originally Posted by Kolenka

It's not hard to lay them out, but it is hard to force light from only 6-10 LEDs to evenly light a square surface.

More ideally, you'd want a large number of lower power LEDs to avoid the shadows. The shadows are there because to get those parts of the screen lit up, you have to bend light more sharply via refraction. The physics of optics shows us that the more you want to bend the light, the more complicated the optics have to be. And to make it worse, the more likely you are to introduce optical aberrations into the layer over the e-ink that cannot be completely removed.

And here, Amazon is trying to take the light from a half-dozen LEDs, refract it down onto the e-Ink display, and then bounce it off the e-ink back out with as little distortion as possible. As someone who knows enough about optics to understand the challenges of this, I'm honestly still somewhat impressed they made it as good as it is. And all you have to do is compare the screens between the PW3 and Voyage to see how much sharper the second-generation layer is in comparison to make higher DPI screens that much nicer (something Amazon doesn't even toot their own horn about).

Optics is one of those things that never really gets any easier. We just figure out even more bizarre techniques to push the boundaries just a bit more.

Don't they tune each led to output the same amount of light before they lay them on top of the eink display,with every ereader being the same size and with the leds all being positioned in the same spots i still don't understand why this happens.

Unless they don't check the leds until they have been placed inside the final product and then say do a QC on every 1 in 100 or something and realise they need to check the leds again.

Or perhaps the issues arises with the layering of the leds on the eink display,not aligning them properly ect

[JoHunt]

Amazon sort of acknowledged that Kindle ereaders have different screen hues in their former Kindle trade-in program (recently revised). The amount you were credited with depended on whether your Kindle screen had a hue or not. I wish I had saved the page which listed the different amounts credited.

This is the first time I have not immediately upgraded my Kindle without having any angst about my decision.

[Josieb1]

After spending the evening reading on my new Kobo GLO HD I've decided to keep it. I paid £90 so for that price it's good enough. The splodging is more a yellow upwards line about 2cms up from the bottom between the Led lights. Now I have added the full screen hack it's not so noticeable and I'm sure with time (like my Voyage yellow top tint) I will become accustomed to it.

It's not like I paid an Oasis price for it.

[Kolenka]

Originally Posted by Jason90

Don't they tune each led to output the same amount of light before they lay them on top of the eink display,with every ereader being the same size and with the leds all being positioned in the same spots i still don't understand why this happens.

Let's assume these are true. There's still a third element here: the transparent layer over the e-ink screen that all this light is being shunted through. And because of the nature of the material, to get even light, you depend on refraction/diffraction to bend the light as it passes through. And optics winds up being all about trade offs. You can't get a "perfect material" really, and so you have all this work to control sharpness, reduce false color, etc. And since Amazon is doing a sort of microscopic etching of the material to redirect the light, the tolerances are probably incredibly tight (if the source I've read is accurate that the etching isn't even a pattern, but changes as the distance from the LEDs grow).

Originally Posted by Jason90

Unless they don't check the leds until they have been placed inside the final product and then say do a QC on every 1 in 100 or something and realise they need to check the leds again.

It is impossible to test every unit that comes off the line without it being a non-trivial cost. Mass production has relied on statistical sampling within batches for decades. So yeah, if you have something with tight tolerances that has to be made cheap, it's actually surprisingly easy to wind up outside those tolerances. But this assumes we know what those tolerances actually are.

Originally Posted by tomsem

My conclusion is that the tolerances involved are too narrow to control perfectly. It is probably the capacitative layer between the glass (or plastic) light guide and the e-ink layer that is responsible for the prism-ing, as it is sprayed on and very thin, so even a small variation in thickness can cause 'special effects'.

It's possible.

[disconnected]

For some reason my brain can tune out general all-over gray blotchiness so I can read perfectly well on my six inch Aura or my PW1.

Unfortunately I couldn't cope with the strong color difference between the top and bottom of my Voyage screen -- every time I turned a page I'd be going directly from the white at the bottom of the first page to the dark yellow at the top of the next page and it was really jarring.

I don't have my Oasis yet so I don't know if the color change from side to side will be easier to ignore.