My evening screen still feels too bright or too blue: a troubleshooting checklist

When a Mac screen still feels harsh late in the evening, the cause is usually one of a handful of things, and most of them take a minute to check. Work through the list below in order, because the early items are the quickest to rule out.

1. Check how warm the screen actually is

Every warmth setting has a floor, and it is easy to assume you are at the warm end when you are not. Look at the current colour temperature, in kelvin, in whatever tool you use. Daytime white on most displays is about 6500 K. Night Shift reaches about 2700 K at its warmest. f.lux goes down to 1200 K. Sundown goes down to 500 K in 100 K steps. If your setting sits near the top of its range, move it down and give your eyes a few minutes to adjust before you judge the result.

2. Check the brightness separately

Warmth and brightness are two different controls. A screen can be quite amber and still very bright, and in a dark room brightness is often what makes it feel harsh. Lower the brightness a few steps and see whether that changes how the screen feels. Sundown dims the display as well as warming it, so if you use it, check both sliders.

3. Check the schedule

If the change is meant to happen automatically, confirm the start time is what you expect. A schedule that starts late, or one that was switched off, will leave the screen at daytime settings for part of the evening. In Sundown you can set a custom schedule so the screen warms and dims at the times you choose.

4. Look at the room as well as the screen

A warm, dim screen next to a bright overhead light can still feel glaring by contrast. Research on evening light has looked at room lighting too: one analysis of 116 young adults found that ordinary room light before bedtime, compared with dim light, suppressed melatonin and delayed its onset in nearly all of them. That study was about room lighting, not screens, but it is a reminder that the screen is only one light source in the room.

5. Decide whether you need a wider range

If you have pushed your current tool as far as it goes and the screen still looks too blue for you, the next step is a tool with a lower floor. The guide Best blue light filter apps for Mac compares several options, and Red screen filter for Mac covers the far end of the range, where the display turns red. Neither a warmer nor a dimmer screen is a medical treatment, and if you have ongoing eye or sleep problems, that is a question for a doctor.