Google Books app has the Night Light mode. It detects the time of the day and adjust the light accordingly.

Screenshot of the app, showing the message 'Introducing Night Light!'

Is there any scientific study that backs up such statement?


Text from image:

As the sun sets, Night Light gradually filters the blue light from your screen, replacing it with a warm, amber light that's better for reading. Turn it on once, and Night Light will always adjust to the perfect setting.

Example: enter image description here

This question has nothing to do with Does reading off a self-luminous tablet impact the quality of sleep? as it has been marked as duplicate, please read both questions and see that they are totally different.

update 2

Answering to comments, with "better for reading" I mean to not causing fatigue, strained and dry eyes, at least no more than a clear background, easier to read improving the reading experience.

May be improving sleep is a side benefit from using an amber background, but I am not asking anything related to improve sleep. As said before, the background color adjust depending the time of the day, not just at night, so the main goal of this technology won't be to have a better sleep, but a better reading experience.

Rephrasing the original question, what are the benefits (if anyone) of filtering "the blue light from your screen, replacing it with a warm, amber light"?

  • Well, on submarines they use red lights at night because it improves contrast. You can see edges better in red light then in other lights. Not sure if its related, but it might.
    – Polygnome
    Commented Jul 24, 2016 at 19:31
  • This seems like an interesting point to start from: justgetflux.com/research.html - apparently there have been multiple studies on this (too numerous to re-post here). Commented Jul 26, 2016 at 14:23
  • Scientific studies are present for amber colored safety glasses as one found here-ncbi.nlm.nih.gov/pubmed/20030543, here-ncbi.nlm.nih.gov/pubmed/20030543 and a review here -well.blogs.nytimes.com/2015/04/07/… but not for amber colored backgrounds in book apps! Commented Jun 18, 2017 at 10:30
  • 2
    Define "that's better for reading". I can write an answer about the neurological benefits of reducing blue light at night time, but it's up for debate whether that can be considered "better for reading". Commented Jun 19, 2017 at 9:06
  • Marcanuy: I understand you have been through this before, but I am not at all convinced this isn't a duplicate. As @Jordy and ReubenB point out, "better for reading" is vague, and probably refers to getting better sleep afterwards, not clarity or eye-strain.
    – Oddthinking
    Commented Jun 22, 2017 at 22:15

1 Answer 1


Amber tinted screens do not make the device better for reading in the sense that they allow you to read more easily.

The purpose of the tint is to diminish the effect that the phone's screen has on your sleep cycle. Studies indicate that bright blue lights can interfere with the body's sleep cycle by changing one's levels of melatonin, a hormone that regulates sleep.

The message means that the tint will make it better for reading at night because of this benefit.

  • 1
    But does it work? This answer is more than a restatement of the claim, but not much more.
    – Oddthinking
    Commented Jun 22, 2017 at 22:13
  • @Oddthinking I'm not aware of any studies that examine reading on a phone with a brown filter. AFAIK the only studies done on this examine blue lights vs orange lights, not smartphones with screen filters. So even though the theoretical basis for this is well-founded, I don't think any study has been done on this feature.
    – Reubend
    Commented Jun 23, 2017 at 3:32
  • So your answer is 'no-one knows'? We'll need a reference to an expert saying that, so we know it isn't just an argument from ignorance.
    – Oddthinking
    Commented Jun 23, 2017 at 6:22

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