The well accepted definition of an e-reader is "a mobile electronic device that is designed primarily for the purpose of reading" (from wikipedia) and most (all?) of those devices are reflective as opposed to LCDs which are backlit.
"They spent five days reading from a paperback and five days from an iPad.". If only iPads were used, I don't believe the word e-reader is appropriate.
If you use an e-ink display without a built-in light, there are no reason this would be any different then using a book (as mentioned in the article but it's not only about "the original kindle"). Also there were tons of studies about the effect of light on sleep and especially blue light emitted by LCDs, most e-reader makers use a warmer light if I'm not mistaken.
> There are a lot of e-book reader with a built-in backlight that can be turned on and off, like the Kindle Paperwhite.
"Paperwhite guides light toward the surface of the display with its built-in front light—unlike back-lit tablets that shine in your eyes" [1]
I have a Kindle Paperwhite, and was surprised to read this article, because I have no trouble sleeping. Apparently the way the light works is the reason for this :)
Thanks for the reference. I am not sure that backlights are the problem though. Just imagine shining a light behind the page of a book (although it's hardly comparable to the level of transparency of Liquid crystals). I would rather bet on the color of the light (warm vs cold). Maybe it's all in my head but when it's sleep time, I hate cold bulbs (and LCDs) while I am not bothered by warm light like a candle or a warm bulb.
Furthermore, it seems to me that with the Paper White's light guided "on the surface of the display", the light shines as much in towards your eyes as it does towards the screen...
Yes but they are totally usable with ambient light with the built-in light turned off as opposed to non-reflective LCDs. As a side-note, if I remember correctly, the built-in light in the Paperwhite is not a backlight but runs on top of the screen, thus using the reflective nature of the e-ink display.
EDIT: I probably should have said "without the built-in light" but wanted to include devices that do not have one to begin with. I am still using one of these :)
> The light emitted by most e-readers is shining directly into the eyes of the reader, whereas from a printed book or the original Kindle, the reader is only exposed to reflected light from the pages of the book.
So it's talking entirely about brightly backlit tablets, not e-readers with e-ink.
Since 2012, Amazon's high-end Kindles (the 2012 Paperwhite, the 2013 Paperwhite and the 2014 Voyage) shine light directly into the eyes. It looks just like a backlit display although technically the light and the diffusion panel are in front of an opaque (e-ink) display, not in back of a translucent (LC) display. On my Paperwhite, it is impossible to turn this light off -- only to dim it.
Also, I dispute the OP's contention that reflected light on s paper book is any better; certainly, a normal bed-side lamp is worse for the sleep of anyone sharing the room with the reader.
EDIT. Although like I just said, an iPad probably has less of a deleterious effect on sleep than a Kindle Paperwhite does, it is probably possible to do better in the current market. Specifically, Samsung makes a tablet (the Tab S, which comes in 10.5- and 8.4-inch versions) with an OLED display, which has the advantage over LCD displays that the portions of the screen that are supposed to be black do not emit any light at all. Especially if used with software that displays red or orange text on a black background (to minimize the blue-ish photons) an OLED display is the best choice in the current smartphone-plus-tablet market AFAICT if protection of sleep is the main consideration.
EDIT. Oops, I forgot to include my main reason for preferring the iPad to the Paperwhite: on iOS, Settings > Accessibility > Invert Colors reverses black and white. Combined with the fact that many iOS apps like Safari and iBooks normally present a white field broken only by text and thin lines, the use of "Invert colors" probably results in less light entering the eye than a Paperwhite since (unless they changed it since I last updated the software on my Paperwithe a couple of months ago) you cannot alter the Paperwhite's default color scheme of black text on a white background. I will concede that the Paperwhite's brightness setting goes a lot dimmer than the iPad's does, but I consider that consideration to be trumped by what I just wrote, and, again, neither Paperwhite nor iPad comes close IMHO to an OLED display used with decent software.
The LEDs in the Paperwhite Kindles do not shine light directly in the eyes: the leds shine from below the screen towards the top end of the screen. As it exits the LEDs, light is reflected inside a light guide from which it exits towards the display from specific holes, much like a leaky fiberoptic cable[1].
The directionality and position of the LEDs, and the existence of the light guide, are precisely the differences which make the Paperwhite unlike a backlit display.
Are there any smartphones/tablets that have the light hit the display surface from the front and then bounce off like the kindle does? I thought they all either used a backlight shining through the display from behind or were an array of tiny little light sources (depending on the screen technology used) - either way the light is being broadcast direct from the source to your eyes; not hitting a surface and emitting diffuse light out.
Old monochrome reflective LCDs used that, but smartphones and tablets are almost always using transmitive screens with backlight (sometimes transflective, like on Nokia N900, but reflective properties are only usable in very bright sunlight).
Kindle Paperwhite however has 100% reflective e-ink screen plus set of LCDs that shine through the light guide layer above the screen. Some people think that makes it better than transmissive LCDs - that's why using Kindle Paperwhite instead of iPad in this test would be much more insightful, as sleep-disturbing properties of transmissive, blue-tinted LCDs are nothing that wasn't known before.
I have a Paper White, as well. I can't imagine the light, when at its dimmest setting would be more trouble for sleep than any LCD thing. And, in fact, soon after I got a Nexus 7 and starting reading with it more often than my Kindle (using Twilight to redden and dim the screen dramatically and using the Kindle app in black background mode), my sleep schedule has kinda gone to hell. It's 3AM here, and I'm probably two hours from sleeping. There are confounding variables (winter always screws me up as I get Seasonal Affective Disorder something fierce), but still, now that I'm thinking about it, I think I'm gonna go back to reading on the Kindle before bed and see if it improves my sleep situation. The Nexus certainly hasn't helped.
For reference for those who don't have a Paper White; when at its dimmest setting, it is probably less than the ambient light in the room from neighbors porch lights and street lights. It is almost completely dark, and looks like an older non-lit Kindle in any room with lights on. I do wish it could turn off completely, however.
The Paperwhite's LEDs front-light the display just like a reading lamp front-lights the pages of your book. It may look just like a backlit display, but the distinction is important.
Rather than the source of the light shining directly into your eyes (iPad), in the Kindle paperwhite the light is directed onto the page, where it is diffused.
This is one reason why I use a European model Samsung Galaxy S3 (GT-I9300) for ebooks. It includes "mDNIe" which gives you very flexible OLED display configuration on rooted phones. You can completely turn off the blue channel and remap blue to green so blue things remain visible. I use the "Galactic Night" app for switching between mDNIe modes.
To further reduce light exposure I use gray (remapped to yellow) text on a black background (very dark because the display is OLED). I set the screen brightness to maximum in FBReader to avoid PWM flicker, and reduce the text brightness to compensate. I also disable the phone indicator LEDs. I don't find reading like this to harm my sleep.
The one problem is that the mDNIe mode very briefly flashes to default when the phone is first turned on from standby. I think this could be fixed with a kernel patch but I just avoid looking at the screen then.
I put a red filter over our nightlight, which seems to work quite well for reading paper books (or non-lit e-readers). Now I've also ordered some amber LED bulbs, without any blue light at all, which should be a more of a permanent solution.
I also ordered an amber filter for my phone, although I think perhaps a better solution would be to not use phones/tablets in bed.. but I'm not sure it's realistic to always avoid the temptation.
The final part of the solution is to have a wake-up light. I had one before, and it's really quite essential up here in the north. But I think it would be beneficial everywhere. Studies showed that people have different times it's natural for them to wake up ("A" and "B" people), and if you wake up earlier than what's natural for you, it affects your performance. Solution? Block out all external light from the bedroom, and use a wake-up light as an artificial sunrise. (Or allow people to come to work/school at different times, but that's not always an option).
The study only seemed to compare An iPad with print books. While I am sure many people who do use an iPad for ebooks I am sure there are many more Kindle readers, which may well have given a different result.
The Kindle Paperwhite has a very blue tinted light. I'm not sure about other lighted eBooks, but I dislike that they specifically called out light emitting vs reflective surfaces. As far as I'm aware the colour of the light makes a much bigger difference to melatonin production than the source of the light.
EDIT: Looking at the actual paper they were definitely aware of this with measurements of the colour spectrums of different tablets, unfortunately not including the Paperwhite. Disappointing journalism skewing the story as normal.
Does it now?? Is there an option to go into standard e-ink/nonlighted mode? I've been considering purchasing one for a while in order to help my eyes at night.
I hope you're not jesting, as this was my first thought. I definitely found it easier to fall asleep and stay asleep after installing Lux on my tablet, and phone. Flux for my computer.
If I disabled Flux -- like I just did -- it's awfully painful! Torture! How did I used to stare at this awfully lit thing for hours on end and expect sleep to be peaceful?!
On a serious note, it'd be interesting to see whether it's the actual 'light exposure' that's hindering the sleeping process, or the 'blue light' that Flux, Lux and others have set out to solve.
Not sure if that is actually a solution? No studies have been done yet (I think) which investigate if there's a 'safe' threshold for amount of light the screen exposes a person to, under which the effects on sleep etc are absent or extremely small. So for all we know it might be better with f.lux, or the same, can only guess.
I've been looking for a laptop with a kindle like screen and a cool ARM processor for ages. My brain gets burned by the backlit screen and my lap gets burned from the steamy hot intel processor. I would be happy to switch to Ubuntu even if I prefer OSX if this became available.
Any kind of bright light at night is going to reduce your melatonin production. This problem goes all the way back to the introduction of incandescent lighting, e-readers are just the latest chapter.
If you look at the progression of artificial lighting, from candles, to incandescent, to halogen incandescent, to fluorescent, to LED, each generation typically increases both the blue light production and the brightness. Such strongly blue spectrum isn't an essential feature of the technology, so I suspect that it's marketing driven because it looks more futuristic.
Additionally, a lot of LED lighting flickers at frequencies that are visible when you move your eyes via the phantom array effect:
https://en.wikipedia.org/wiki/Flicker_fusion_threshold#Visua...
I personally find this very annoying, but even if you don't consciously notice this it's something not found in nature, and I'm not aware of any long term safety studies.
I'm very skeptical of these changes. Humans have a poor track record of predicting safety implications of new technology (eg. radioactive materials as health products, leaded gasoline, etc).
I use the Kindle app under "sepia" mode to help mitigate this sort of problem, somewhat. It works much f.lux does, though I don't think it's as extreme as f.lux's colors.
Yup. Gives out nasty 'blue light' as spoken about in the article. Try Flux[1], it'll change your life. If you doubt me, install it and have it run at night and then after an hour of browsing HN, disable it...
This article is poorly titled. Disappointing since the BBC is capable of better journalism than this. They should be specific that it is backlit LCD screens (especially LED backlights since their spectrum is predominantly in the blue range which simulates morning) rather than what is typically meant when someone says E-readers, ie: readers that use E-Ink panels which are not backlit and thus rely on ambient light.
I agree that BBC is capable of better journalism. This resonates with the article 'Why so many health articles are junk' posted 5 days ago on HN. https://news.ycombinator.com/item?id=8764871
The study ignores real e-readers with e-paper displays that mimic dead tree books extremely well. They also have a sample size of 6 for each of the 2 groups...
"They spent five days reading from a paperback and five days from an iPad.". If only iPads were used, I don't believe the word e-reader is appropriate.
If you use an e-ink display without a built-in light, there are no reason this would be any different then using a book (as mentioned in the article but it's not only about "the original kindle"). Also there were tons of studies about the effect of light on sleep and especially blue light emitted by LCDs, most e-reader makers use a warmer light if I'm not mistaken.
EDIT: elaborating