iOS 9.3's Night Shift, explored: what is it, how to enable and manage it

One of the highlights of the recently released iOS 9.3 is Night Shift, a new iOS feature that aims to reduce eyestrain and make it easy for you to fall asleep. This is a brand new feature for iOS, though the concept behind it isn't - various apps and programs that boast similar functionalities have been available on most platforms for a long time now, with one of the most popular ones being f.lux. For a brief time, it was also available on the iPhone, but Apple killed it off as it reportedly violated the company's Developer Program Agreement.

Night Shift aims to keep your organism in line with the 24-hour "circadian rhythm", which is crucial for your sleep patterns. Indeed, numerous studies have found that if you're subjecting yourself to bright blue light right before bed, you are messing up with the levels of melatonin in your body. Turns out melatonin is a pretty important hormone that regulates your sleep timing - it is tied with the circadian rhythm and the natural lighting conditions. 

Its synthesis in the human body usually accelerates once evening nears and lighting begins to dim down. Unfortunately, Blue light with a wavelength in the range between 460 and 480nm has been found to mess up your body's melatonin synthesis, and hence, with your sleep. Night Shift wants to be best buddies with your melatonin by greatly reducing the amount of blue hues your display emits. It does this by shifting the color temperature of the display towards the warmer end of the spectrum. 

Though Night Shift can be enabled manually at your will, users are allowed to leave iOS take care of it; if so, your current location and the time of day will be taken into account as to whether it should be turned on or off. The feature is similar to your device's brightness slider, allowing you to freely set up a preferable amount of blue light reduction. After getting hold of iOS 9.3 on one of our resident iOS devices (an iPhone 6 Plus), one thing led to another, and we found ourselves with a colorimeter in hand, measuring to what extent Night Shift re-adjusts the color temperature. 

Here's follow our findings. With Night Shift off, the color temperature of our iPhone 6 Plus stood at 7448 Kelvin. Enabling Night Shift and leaving it in its "cooler" position shifted the display's spectrum to 6395 K, while the warmest we could go was as low as 3026 K. Users are allowed to adjust the color temperature anywhere in-between. 

SettingColor temperature
Night Shift off7448K
Night Shift on, coolest setting6395K
Night Shift on, average setting5415K
Night Shift on, warmest setting3026K
*Disclaimer: As measured on our resident Apple iPhone 6 Plus; your results may vary.

All clear? Okay, let's see how one manages Night Shift - we are about to show you the ropes on how to enable, disable, and set it up! By the way, if you're rocking an Android device, we have a succinct selection of apps with similar functionality for your handset - check them out here.



1. hafini_27

Posts: 951; Member since: Oct 31, 2013

I remembered there was a very popular app on the App store that does exactly the same thing but got pulled by Apple.

4. GreenMan

Posts: 2698; Member since: Nov 09, 2015

@hafini_27 Yeah, and there's was an App on on The App store that could detect THE BIG FOOT via GPS... Too bad, it got pulled by Apple.

9. illusionmist

Posts: 157; Member since: Jan 29, 2013

f.lux was never on the App Store. Some code was released for the sideloading capability on iOS 9, but they misused it (try to trick Xcode to load a compiled binary) so Apple told them to stop. The other truly open source ones (like GoodNight which I'm still using) are still alive and well.

19. hafini_27

Posts: 951; Member since: Oct 31, 2013

It is a very popular app. I only remembered that Apple blocked it from App store. Did not know that was the reason.

10. zeeBomb

Posts: 2318; Member since: Aug 14, 2014

Damn...circadian rhythm...words I have never heard before and I feel like a scholar once ivlearned what it meant! And the night mode slider? A.k.a dirty way to calibrate iPhone display

2. submar

Posts: 713; Member since: Sep 19, 2014

try bluelight filter on android

3. Jimrod

Posts: 1605; Member since: Sep 22, 2014

Well it's a new feature at least, the last few iOS updates haven't had much going on - and this one means you can manually calibrate your screen to a colour temp you prefer without having to Jailbreak too. Can't complain.

12. Unordinary unregistered

Especially since it's a "." update and not iOS 10,11,12, etc.

5. hortizano

Posts: 294; Member since: May 22, 2013

f.lux didn't violate any regulation.. they just grabbed the idea and dumped them.. as Apple always do.

17. ibend

Posts: 6747; Member since: Sep 30, 2014

just like when they block Google Maps, and release Apple Map (which is a huge failure, lol)

27. AlikMalix unregistered

When did Apple Block anything from Google, especially maps? They had to remove it from native list of apps when license expired between Apple and Google (same for YouTube) because Google wanted to charge iOS users for step by step directions. If I remember correctly Apple had to come up with it's own maps in like 2 months... Google got greedy, and you're blaming apple for "blocking" Google maps? are you serious?

35. AlikMalix unregistered

f.lux used a non Apple's XCode - that's a security problem...

6. jove39

Posts: 2147; Member since: Oct 18, 2011

CM12 had this feature for over a year now.

13. Wiencon

Posts: 2278; Member since: Aug 06, 2014

f.lux had it for 7 years now

14. Unordinary unregistered

Ive had this on my previous iPhones for yearS. Before F.lux, there was Eyeluv or or whatever it was called 6 years ago.

7. TyrionLannister unregistered

So the night shift on bluest has more accurate whites than the default ones!

8. kane74

Posts: 44; Member since: Jan 24, 2014

Screen Filter on Android. There were some apps which did that already with a jailbroken IOS device

11. ArtSim98

Posts: 3535; Member since: Dec 21, 2012

I use Twilight on Android

15. twens

Posts: 1180; Member since: Feb 25, 2012

Yet another old feature that tech sites will hype the s**t out of just because it's on iPhones. Every jail breaker knows this has been around for years. There are countless of endless features that can be found in Cydia and touchwiz but they don't get hyped. Once it lands on iOS it gets mentioned. This behavior pisses me off.

16. Jimrod

Posts: 1605; Member since: Sep 22, 2014

You're the idiot who clicked on the iOS article you hate to see so much of.

23. twens

Posts: 1180; Member since: Feb 25, 2012

You're just butt hurt jumping to apples rescue.

24. Jimrod

Posts: 1605; Member since: Sep 22, 2014

No, I called you an idiot. You click on articles featuring something you hate so you can get all hurt and emotional. Where did I jump to Apple's rescue? Oh that's right, in your tiny little mind... Oh, what's that on your shoulder? Ahh, an enormous chip, I can't seem to get it off... :\

26. submar

Posts: 713; Member since: Sep 19, 2014


34. Jimrod

Posts: 1605; Member since: Sep 22, 2014

Amazing comeback.

28. AlikMalix unregistered

Twins because 95% or more do not jailbreak (including me) nor heard of apps like f.lux until now. Apple sees a beneficial feature that all users should have - so it adds it to the OS - why does that piss you off? You should be pissed off that your favorite ___________ manufacturer doesnt properly let public understand it's features or make them work properly - that their implementations arent impactful enough to make the headline. Whatever the reason - even if it's just tech sites that favor Apple's version - it's not their fault, but their FULL RIGHT to publish whatever they deem worthy. Sorry, dude, but unless it's Apple - it ain't interesting... Wait! I know, you should start a popular tech website and outline all the features of Samsung, so the public can understand them and why they're needed...

30. Slowpoke

Posts: 23; Member since: Sep 30, 2015

twens, while Jimrod has a point that you did click a hype article so that Apple would have free advertising, I agree with your point whole heartedly. Apple didn't invent this feature and stole it from many hard working programmers who deserved to make money from it. Like the built in flashlight feature. I miss using an app that would pop up an advertisement blocking the on/off switch right when I wanted to turn on the lite. It was pure brilliance. Now that app gets hardly any business.

32. AlikMalix unregistered

LoL... I love this post... but everyone is right, Apple didnt invent this feature nor did they research the whole eye rhythm thingy (nor did f.lux or others)... so lets give the biologists credit while we're at it... Apple as far as I've seen isnt taking credit as an innovator of this (the haters are labeling AGAIN as if apple is taking credit for this innovation - non of which is true)... Apple just sees this as a must have feature and added to OS level - why are people so angry at apple for this? I bet even Apple iOS engineers are sitting there going "dang, Mike, I had no idea people gonna be so hyped about this niteshift thing!!"... lol

36. stormychel

Posts: 1; Member since: Jan 21, 2016

Because it's the only OS that matters. Deal with it.

18. adecvat

Posts: 646; Member since: Nov 15, 2013

Cool feature. Unreachable for Samsung amoled devices that all have flickering display - r.i.p. your eyes.

20. Awaragardiyan unregistered

i remember xiaomi added a similar feature in miui in oct 15. it even has apps filter.

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