What is True Tone？
The True Tone technology first made its appearance on the iPad Pro, which launched in March 2016, but it has subsequently been added to devices including iPhones from the iPhone 8 and newer, as well as some of Apple's flagship laptop models that launched in mid-2018 and later.
How does True Tone work?
Devices featuring True Tone technology feature sensors that measure the ambient light colour and brightness. The device then uses this information to automatically adjust its display, so it can correct white point and illumination based on your environmental lighting in order to render the right kinds of white under any conditions. This technology isn't new as some desktop monitors have been offering it for a long time.
The thing to remember is that the human optical system is constantly comparing near-white to perfectly white, and that a "better" white can affect our perceived contrast of whatever we're looking at, meaning an adjusted white point should be more comfortable on our eyes. It also means that devices with True Tone should be more readable in direct sunlight, thus improving their usability ever so subtly.
There's another important element here for creatives though, and that's ensuring that the colours displayed remain consistent and accurate. In terms of the MacBooks with True Tone, the technology makes for a natural viewing experience that's not skewed by ambient light.
Here's how Apple explained its True Tone display when it was first launched: "The 9.7-inch iPad Pro features advanced display technologies, including a True Tone display, which uses new four-channel sensors to dynamically adjust the white balance of the display to match the light around you for a more natural and accurate, paper-white viewing experience."
Does True Tone need to be enabled?
True Tone is switched on by default, but it can be enabled or disabled.
On iPhone and iPad: Open Settings > Display & Brightness > Toggle True Tone on or off.
On Mac: Choose Apple menu in the top left corner > System Preferences > Displays > Click the Display tab > Tick or untick True Tone.
Why would you switch off True Tone? Personal preference - like Night Shift or auto-brightness, sometimes you just want things to stay static and not be changing while you're looking at them.
Is True Tone related to Night Shift?
Night Shift was a feature Apple introduced in iOS 9.3. It uses the iPad or iPhone's clock and geolocation to automatically adjust the colours in the display to the warmer end of the spectrum after dark. The idea is the reduce exposure to blue light, which stimulates the brain and can keep you awake, leading to a bad night's sleep.
Night Shift works like True Tone, but for a different reason. It delivers a warmer screen closer to your bed time in order to reduce the amount of blue light emitted from the screen.
As a result, the display appears more orange. A warmer display should be much more comfortable for late-night reading when ambient light is likely to be lower though. Apple suggests that blue light can affect our sleep by throwing off our circadian rhythm, which moderates our body clock.
The Night Shift setting suppress the secretion of melatonin, too. Harvard researchers and their colleagues have even proved this with experiments so, Night Shift should reduce the negative effects of using your device at night. You can adjust Night Shift settings, schedule it and change the colour temperature. To do this:
On iPhone: Open Settings > Display & Brightness > Night Shift.
On Mac: Choose Apple menu in the top left corner > System Preferences > Displays > Click the Night Shirt tab.