iPhone’s hidden ‘night vision’ mode

 iPhone's Hidden Red Screen : How to enable it

Night Shift, Dark Mode, Reduce White Point and Zoom's Low Light Filter all help reduce the harmful effects on your body's clock which bright iPhone and iPad screens have at night. But there's another option on iOS and iPadOS that turns your entire display red, and it's useful for so much more than just late-night browsing in bed. This is especially helpful at night and when we first wake up, since the regular light the iPhone displays can cause fatigue and harm our eyes. Apple already offers some built-in options to protect our eyes, which includes:-

Night Mode, which reduces blue light and reduces fatigue

Dark mode, which switches the bright whites to black or dark grey colours, putting less stress on your eyes

True Tone, which adjusts the display colour based on your environment

Warn that the iPhone is too close to your face

The brightness slider, Reduce White Point, and Zoom's Low Light Filter all dim the display, but Night Shift cancels out blue light frequencies, resulting in an orange hue which can help you get to sleep more easily. Dark Mode switches all the bright whites to black or dark grey colours, putting less stress on your eyes. The iPhone has a hidden “night vision” feature which turns your screen red. More than giving a spy movie vibe, a red screen could help sharpen people’s night vision by reducing the harmful effect of the bright displays we stare at all day. Colour Tint overlays your entire screen with a coloured filter, such as a pure red filter, which has its own benefits. Red light is more challenging to see than other light frequencies, so it tricks our eyes into thinking it's less bright than it really is. This means you can look at a red screen in a dark room, and your dilated pupils won't have to adjust as much to the light. Additionally, when you look away from the red screen, your eyes adapt much more quickly to the darkness around you.

There are benefits to turning your iPhone screen red. The colour is more difficult to see than other light frequencies, so it tricks our eyes into thinking it’s less bright than it actually is. In a dark room, for example, your pupils won’t have to adjust as much to the light. Also, when you look away, your eyes adapt quicker to the darkness around you. In addition, this iPhone hidden feature can also help you use star map apps for astronomy, sneaking your phone at the theatre's, eyesight animals or when you check your phone in the middle of the night. Apple's hidden Colour Tint feature could even use your iPhone's screen as a makeshift red-lens flashlight for red-light readable paper maps. And as a reader pointed out, many animals have a hard time seeing red, so a red filter will let you use your iPhone or iPad while hunting at night. With that in mind, Apple has this hidden night vision mode. Following is the procedure to enable it:-

On your iPhone, open Settings

In the Accessibility tab, search for Display & Text Size

Turn on Colour Filters and select Colour Tint

Move Intensity and Hue to the far-right position for the full red-screen effect.

Enable Red Tint

Simply go to the Colour Filters menu buried in Settings to try out the hidden feature. On iOS 17 or iPadOS 17, head to the following location in your preferences. This is also where you'll find it on older software dating back to iOS 13 and iPadOS 13, though Colour Filters' first appearance was on iOS 10.

Settings » Accessibility » Display & Text Size » Colour Filters

Next, toggle on the "Colour Filters" switch and select "Colour Tint" as your filter. The Intensity and Hue sliders should be in the far-right position to get the full red screen effect, so move the controls on those if they're not already there. You can't capture the effect in screenshots, but it's certainly dramatic. And because your iPhone or iPad emits only red light, it will be much easier to use in dark environments to maintain night vision without disturbing your eyes.

Add a Shortcut for Your Red Tint (Optional)

If you want to go back and forth between your new red tint and regular bright non-tinted screen, it'd be inconvenient to keep going into the "Colour Filters" menu in Settings to toggle the red filter ON or OFF. To turn the red screen ON or OFF faster, following few options are available:-

Accessibility Shortcut (Triple-Click)

With the Accessibility Shortcut feature, you can triple-click the Side, Home, or Top button on your iPhone or iPad to switch between the standard screen and red tint. To set it up, go to the "Accessibility Shortcut" menu at the bottom of the Accessibility settings. Choose "Colour Filters" from the list, and you're done.

Settings » Accessibility » Accessibility Shortcut » Colour Filters

If you've enabled two or more options for the Accessibility Shortcut, such as Colour Tint with Background Sounds, Magnifier, Smart Invert, Voice Control, or Zoom, a menu will appear when you triple-click. You'll need to choose "Colour Filters" from there. It's a little slower but necessary if you like using a lot of these cool triple-click shortcuts.

Accessibility Shortcut (Control Centre)

You can add the Accessibility Shortcuts control and access Colour Filters from there. First, you need to follow the instructions given in above Option for assigning Colour Filters to the Accessibility Shortcut. Then, add the proper control for Control Centre if it's not already there.

Settings » Control Centre » Accessibility Shortcuts

If you only have Colour Filters assigned, tapping the Accessibility Shortcuts control in Control Centre will toggle it. Otherwise, a menu will open, and you will have to select Colour Filters.

Siri

You may also be able to use Siri to toggle the red filter, but it only seems to work on iOS 15 and iOS 16, as well as on iPadOS 15 and iPadOS 16. You may also have success on iOS 17 and iPadOS 17. Say "Hey Siri" or, as of iOS 17 and iPadOS 17, just "Siri" with one of the commands below to enable or disable it. If you don't use "Hey Siri" or "Siri" voice activation, long-press the Side, Home, or Top button, and say the command without the vocative.

"Turn [on/off] Colour Filters."

"Turn [on/off] Colour Tint."

"Turn Colour Filters [on/off]."

"Turn Colour Tint [on/off]."

"[Enable/disable] Colour Filters."

"[Enable/disable] Colour Tint."

"Toggle Colour Tint."

If you use the Home app to control smart lights and other smart products, Siri may think you're talking about a room or HomeKit or Matter accessory instead of the Accessibility tool. To avoid this, go to Option given below. On 17.0 and later, Siri frequently says it doesn't understand or can't perform the action even without Home set up. 

Custom Shortcut

On iOS 15 and iPadOS 15 and earlier, the Shortcuts app does not have any actions to toggle Colour Filters or Colour Tint, so you can't create a Home Screen button to press whenever you want the red filter. However, iOS 16 and iPadOS 16 and later do have a "Set Colour Filters" action. For the most straightforward implementation: Start a new shortcut, add the "Set Colour Filters" action, and change "Turn" to "Toggle." Then, tap the shortcut's current name, choose "Rename," and rename it if you'd like. Whatever name is here will also work as a Siri command (see Option given above). After renaming or not, tap the share button and select "Add to Home Screen." Alternatively, you can tap the info (i) button in the bottom toolbar of the shortcut editor and select "Add to Home Screen." Or you can tap the shortcut's name and hit "Add to Home Screen." Change the icon if you wish, then tap "Add" to see its icon on your Home Screen. Tap that to turn ON the colour tint, then again to turn it OFF.

Back Tap (iPhone Only)

If you don't like using Control Centre or triple-clicking your iPhone's Side or Home button, you can use the Back Tap feature instead. This only works on iOS 14 and later.

Settings » Accessibility » Touch » Back Tap

Choose "Double Tap" or "Triple Tap" and assign "Colour Filters" to it. Then, you'll toggle your red screen filter on or off whenever you double-tap or triple-tap the back of your iPhone.