Dark Mode vs Night Shift vs True Tone on Mac

Last Updated: September 2026

Night Shift on a Mac warms the white point of your display, so whites look more yellow and carry less blue, from a schedule you set or until you turn it off. It doesn't change brightness, and it doesn't touch the interface colours. That's Dark Mode's job, and True Tone does a third, separate one.

These three switches sit a few centimetres apart in System Settings, and most people assume they're three strengths of the same thing. They aren't. Each one changes a different property of the light your screen sends out. Two of them change its colour: True Tone to match the room, Night Shift to make it warmer on a schedule. Below is what each one does, according to Apple's own documentation, what the circadian research says a screen has to change, and how to set the three up together for the evening.

What does Night Shift do on Mac?

Night Shift shifts your display's colours toward the warm end of the spectrum. Apple's wording is that "warmer color temperatures show more yellow and less blue". You pick how warm with a slider, and it runs on a custom schedule you set, on Apple's own after-dark schedule, or manually until the next day.

Apple's Night Shift support page says it "automatically shifts the colors of your display to the warmer end of the color spectrum after dark" when you schedule it, and returns the display to normal in the morning. You'll find it under System Settings, Displays, Night Shift.

What Apple doesn't publish is a number. The warmest point of the slider is widely cited as roughly 2700 K, and that's the figure we use, but it's a common figure rather than an Apple specification, and your display's own characteristics shape what you actually see. Apple says as much about external monitors: "Night Shift performance on external displays depends on the characteristics of the display."

Two things Night Shift leaves alone: brightness, and the layout of light and dark on the screen. A white web page under Night Shift is a yellower white page at the same brightness.

Dark Mode, Night Shift and True Tone at a glance

Dark Mode changes the interface colours, Night Shift changes the white point, and True Tone matches the white point to the room. Here is each one side by side, taken from Apple's support pages.

The column that matters most at night is the fourth one. Night Shift is the only one of the three built to move your screen warmer and keep it there.

Dark Mode: a darker interface, not a warmer screen

Dark Mode swaps white window backgrounds for dark grey ones, which cuts how much light those pixels emit. It doesn't change the colour of that light, because a grey pixel is made by driving the red, green and blue subpixels in the same ratio as a white one, just lower.

In our Dark Mode post we worked through the numbers from Apple's own system colours on macOS 26.5.1. The dark window background, #1E1E1E, comes out at 0.013 relative luminance against 1.000 for white, roughly 77 times lower per empty pixel. Across a whole page the gap is smaller, because the text flips from dark to bright: about 20 times lower for a sparse page, 11 times for typical prose, and 5 times for dense code. Those are sRGB relative-luminance calculations from pixel values, not a photometer reading of emitted light, and your own panel and brightness setting will move them.

So Dark Mode is a real cut in the amount of light, but only inside apps that honour it. Open a PDF, a white website or a photo and you're back to a full white field at the same cool white point, because the white text in Dark Mode and the white page in a browser are both still full-spectrum white.

One detail from Apple's Night Shift page connects the two: if your Appearance setting is Auto, "your Mac switches appearance from light to dark based on the Night Shift schedule you set". Set one schedule and both follow it.

True Tone: white balance that follows the room

True Tone adjusts your display to match the light around it. It's a white-balance feature, not a night feature, and it can move the screen cooler as easily as warmer.

Apple's True Tone support page describes it this way: it "uses advanced multichannel sensors to adjust the color and intensity of your display and Touch Bar to match the ambient light, so that images appear more natural." In practice that means a white page is meant to read as the same white under a warm lamp as it does in daylight.

That has a consequence people don't expect. Because True Tone follows the room, a desk lit by a cool LED panel or a daylight bulb will pull the screen cooler, and a room lit by warm lamps will pull it warmer. It isn't aiming at any particular colour temperature. It's aiming at the room.

Apple also says you can use True Tone and Night Shift at the same time, and that some accessibility settings, such as invert colours, grayscale or increased contrast, might turn True Tone off. On external displays it works with Apple's own Studio and Pro displays, and on other displays up to 32 inches (not TVs or projectors) when they're connected to a Mac laptop with its lid open or an iMac from 2020 or later.

Does any of them protect your sleep or eyes?

None of the three has been shown to protect sleep or eyes, and we won't claim they do. What the research shows is which properties of evening light the body clock responds to, and that tells you which switch touches which one.

The foundation is the action spectrum work. George Brainard and colleagues at Thomas Jefferson University (PMID 11487664) exposed 72 healthy adults to single wavelengths of light in the middle of the night and measured melatonin. The most potent region was 446 to 477 nm, blue light, and the shape of the curve didn't match the rods and cones we see with. Kavita Thapan, Josephine Arendt and Debra Skene at the University of Surrey (PMID 11507175) reached the same conclusion independently the same year, and at Brown University David Berson's lab (PMID 11834835) showed the retinal ganglion cells that feed the body clock respond to light directly.

At Brigham and Women's Hospital, Steven Lockley, George Brainard and Charles Czeisler (PMID 12970330) found that 460 nm blue light shifted the melatonin rhythm and suppressed melatonin more strongly than 555 nm green light at equal photon density. Wavelength matters, and so does how long you're exposed.

Read against that, the three switches split cleanly. Dark Mode lowers the amount of light but not its colour. Night Shift and True Tone change the colour, and only Night Shift is aimed at warm. None of them lowers the brightness floor.

That last point has one direct test on Apple's own software. Rohan Nagare, Barbara Plitnick and Mariana Figueiro at the Lighting Research Center (PMID 31191118) compared iPad Night Shift at low and high colour temperature settings and found melatonin suppression did not significantly differ between them. Their reading was that changing a display's spectrum without changing its brightness may be insufficient.

One human study of cutting short wavelengths used glasses, not screens. Ostrin et al. (2017) found blue-blocking lenses raised nocturnal melatonin ~58% in healthy adults, who also slept ~24 minutes longer (PMID 28656675). That was tinted lenses worn for hours each evening, and it says nothing about Night Shift, Dark Mode or any screen app. We compare the two approaches in blue light glasses vs screen warmth, and the full reference list is on our science page.

Using all three together, and the Kelvin the built-ins can't reach

Use Dark Mode for less light, Night Shift for warmer light, and decide on True Tone deliberately rather than leaving it to the room. Then, if you want the screen warmer and dimmer than macOS allows, that's a separate tool.

1. Set Appearance to Auto in System Settings, so Dark Mode follows your Night Shift schedule.
2. In Displays, Night Shift, choose Custom and set the hours you actually use your Mac in the evening. Drag the slider to the warm end.
3. Look at True Tone once in the evening light you actually sit in. If the room is lit cool, it will pull the screen cooler, and turning it off keeps the white point where you set it.
4. Lower the brightness slider as the room gets darker. True Tone adjusts colour and intensity to match ambient light, so check the level by eye and adjust it by hand as needed.

Past that, macOS stops. Night Shift's warmest is roughly 2700 K, and the brightness slider has a floor. If you want to go further, our guide to colour temperature explains what the Kelvin numbers mean on a screen, and our Night Shift alternatives roundup covers the other options.

Sundown is the one we make. It's a menu bar app with a Kelvin ladder from 6500 K down to 500 K in 100 K steps, an intensity scale from 0 to 4.0, and gamma-curve dimming that takes the screen darker than the brightness slider allows. As one example, you could set a custom schedule that holds 1200 K through the evening and drops to 500 K for the last hour before bed, alongside Dark Mode. Those are settings, not a prescription, and we don't claim a sleep outcome for them. Our Sundown vs Night Shift comparison sets the two side by side.

The Sleep Foundation's overview of blue light and sleep puts it plainly: the most effective step is to dim the lights in your home and turn devices off after dark. When the laptop has to stay open, make it warmer and dimmer.

Frequently Asked Questions

Does Night Shift protect your eyes?

There's no evidence it does. Night Shift warms the display's white point and leaves brightness alone. A Lighting Research Center study of iPad Night Shift found melatonin suppression didn't significantly differ between its warm and cool settings, suggesting colour alone may be insufficient.

Should I use Dark Mode or Night Shift?

Both, because they change different things. Dark Mode lowers how much light apps emit but keeps the same white point. Night Shift makes all light warmer but keeps the same brightness. With Appearance set to Auto, Dark Mode follows the Night Shift schedule.

Should True Tone be on at night?

It depends on your room. True Tone matches the ambient light, so a cool-lit room pulls the screen cooler and warm lamps pull it warmer. If you want the white point Night Shift sets to stay put, turn True Tone off in the evening.

Night Shift stops at roughly 2700 K. Sundown goes down to 500 K and dims below the macOS minimum, on a schedule you set. Start your 7-day free trial at trysundown.com.