Lower colour temperature to reduce eye strain

[teidon]

It is my belief that too high colour temperature causes eye strain when you look at any kind of display for long periods of time. Colour temperature can basically be simplified to "how white a white colour is". If you for example take any real world item that you think is white (piece of paper, Apple charger, a wall...) and compare it to white on any display (for example google.com's background is pure white) you have around, you will likely notice that the white on the display is much more whiter than any white object you can find. This difference in ambient colour temperature and the colour temperature on your display makes it somewhat uncomfortable to look at the display and causes eye strain, especially if you read text on white background a lot through out the day.

Now in iOS 10 there is a way to lower the colour temperature using the new Colour Filters feature. It's a bit "hacky" and I hope Apple would provide a better way to do it, but for now this will have to do.

1. Make sure Night Shift is turned off
2. Turn on Colour Filters in Settings -> General -> Accessibility -> Display Accommodations -> Colour Filters
3. Select the fourth option: Colour Tint
4. Slide the Intensity slider to maximum
5. Find yellow colour using the Hue slider. You can tint it slightly to orange if you like, but I recommend yellow / mostly yellow.
6. Adjust the Intensity slider to your preference. I have it at about a third way from left.

You can continue using Night Shift as normal. It will lower the colour temperature even more when the sun sets, which is good because the ambient colour temperature will likely be even lower at that time.

 

[Shirasaki]

First I appreciate your time and effort to write this post.
But after a brief testing, "colour filter" is not designed to help reducing Eye strain. It is designed to help colour blind people to correctly distinguish colour displayed on your device. Night shift and "reduce white points" can help more on this case.
I tried to apply colour filter and soon realise none of those settings fit my need anyway.

 

[teidon]

But after a brief testing, "colour filter" is not designed to help reducing Eye strain. It is designed to help colour blind people to correctly distinguish colour displayed on your device.

True, but you can still use the feature for other purposes. For example developers could activate the colour blind filters to check that their apps are usable for colour blind.

Night shift and "reduce white points" can help more on this case.

The problem with Night Shift is that it changes colour temperature only between sunset and sunrise. You can of course set it to be on the whole day, but then the the colour temperature will be same the whole day, even though it would be better if the colour temperature is lower after sunset.

Reducing white point is also one way to make the whites more bearable to look at, but it doesn't reduce the amount of blue light the display emits. It's the blue light that's mostly the problem, and reducing it turns the display yellowish. That's why applying a yellow filter makes it more comfortable to look at the screen.

 

[Shirasaki]

True, but you can still use the feature for other purposes. For example developers could activate the colour blind filters to check that their apps are usable for colour blind.


The problem with Night Shift is that it changes colour temperature only between sunset and sunrise. You can of course set it to be on the whole day, but then the the colour temperature will be same the whole day, even though it would be better if the colour temperature is lower after sunset.

Reducing white point is also one way to make the whites more bearable to look at, but it doesn't reduce the amount of blue light the display emits. It's the blue light that's mostly the problem, and reducing it turns the display yellowish. That's why applying a yellow filter makes it more comfortable to look at the screen.

The original design purpose of Night shift, or even earlier, flux, is to reduce the blue light emission to human eyes. So it works better when ambient light is not that strong, or at night, not 24 hours a day, seven days a week.

Reducing White point reduces the density of white light, which of course helps reducing eye strain. And it does not actually change the colour tint on screen, which is good for colour intensive tasks.

Another reason why I say colour filter introduced in iOS 10 is not used for it is because it filters certain section of spectrum rather than adjusting colour temperature. That "yellow" looks not like the yellow achieved in flux and night shift. I have tried it many times but still fail to think "it feels better".