Turns out that the Paperwhite doesnâ€™t have a backlight per se. Instead, four bright LEDs at the bottom of the display focus downward, away from your eyes, and fire into diffraction grids that help to spread the light around smoothly.
But it isn’t perfect:
I only have one complaint: The lighting on my demo unit is slightly uneven at the very bottom. With the backlight set in a certain way (you can adjust the levels to suit the room), I can see a couple of shadows that intrude slightly into the pageâ€™s bottom line of text. But it was more of an aesthetic problem than a functional one, and in any case, if the shadows bug you, Amazon has a 30-day, no-questions-asked return policy on the Kindle.
I’m willing to bet anyone who notices the shadows will be bugged by them. It’s an imperfection; this kind of stuff needs to be perfect when it comes to a device whose total purpose is to display content for us to read.
2012.10.13: Amazon responds to not perfectly even built-in light:
Under certain lighting conditions, the illumination at the bottom of the screen from the built-in light is not perfectly even. See examples of how the screen looks in different lighting conditions. These variations are normal and are located primarily in the margin where text is not present. The illumination is more even than that created by a book light or lighted cover. The contrast, resolution and illumination of the Paperwhite display is a significant step-up from our prior generation.
These variations should not be normal.
Update 2012.10.17: Cesar Torres, Ars Technica:
The Kindle Paperwhiteâ€™s display has been bumped up to 212 ppi, more than a 25 percent increase. The extra resolution is most noticeable when reading small print, as the smallest font settings look sharp and crisp. It’s this high-contrast display that makes the Kindle a great choice for people who read a lot of paper books and want to move to an e-reader. There is a stillness and sense of quiet in the E Ink display that really mimics paper nicely; a feeling that CRTs and LEDs cannot compete with.
A couple of days ago I finished reading Instant and what a full sensory experience it was. And it wasn’t because of embedded videos or audio. E Ink can mimic paper in terms of the visual experience, but that’s where it stops. Every other part of the reading experience is overwhelmed by plastic. As you can guess I’m not a big fan of E Ink, especially when compared to a real book. If you want to take the dive from analog to digital, go all the way; get a Kindle Fire HD, a Google Nexus 7, or an iPad. They’re mostly plastic too, but you get audio, photos, videos, interactivity, all in brilliant color.
What in tarnation is this suppose to mean: “[…] a feeling that CRTs and LEDs cannot compete with.” LEDs? You mean those big LED billboards we see in Vegas? Has anyone tried reading a book off of one of those? Of course not! Yes, I know; I’m overreacting, a bit. Just so everyone knows: a LCD with a LED backlight doesn’t transform a LCD into a LED. Here are two examples of how it is properly referenced: LED-backlit LCD or LCD with LED backlight. But what’s the point? Almost all modern LCDs use LEDs as the light source in the backlight unit (BLU). Thanks Samsung marketing for confusing the hell out of everyone. I guess Torres got confused, too; he meant to write LCDs I’m sure. But everything after the semicolon simply doesn’t make sense: When has CRT been hailed as a paper replacement display technology?
As I took the brightness up, I found spots along the bottom edge of the screen. These discolorations are quite ugly and actually a bit distracting if you have your margins set very narrow inside the screen. These screen defects felt much like the mura defects on LCD screens.
I wouldn’t call it a discoloration since there is no color on the E Ink display, but the problem is real and instead of passing it off as normal Amazon should take it like a man, admit it’s a design and/or manufacturing flaw, fix it and offer replacements for these defective Kindle Paperwhite units.