StillColor for Mac Disables Temporal Dithering to Reduce Eye Strain and Flicker
Some Mac users who are sensitive to eye strain and PWM display flickering have turned to a small free utility called StillColor to modify how MacOS renders colors on their screen. The StillColor tool has a feature that can disable something called “temporal dithering”, a usually imperceptible display technique that alternates pixel colors at the displays refresh rate, tricking the eyes into experiencing a wider range of colors than are truly present.
This temporal dithering feature has been reported to cause eye strain, headaches, fatigue, nausea, difficulty focusing, and various other physical symptoms, in users who are sensitive to this technology.
And that’s where the Stillcolor app for Mac comes in, which allows you to disable the color dithering feature, potentially relieving eye strain and fatigue symptoms for users who are impacted by the flickering color dithering feature.
On modern Mac’s, the temporal dithering feature happens automatically at the GPU and display level which causes the subtle flicker, and there is no setting in MacOS to disable it. While the vast majority of Mac users do not even notice this feature, for those who do, it can be jarring and uncomfortable to use certain displays. Often, the same users who are sensitive to PWM (Pulse Width Modulation, a complaint of iPhone and iPad displays too), are also sensitive to the subtle flickering from temporal dithering, and therefore those users may benefit from disabling the feature with Stillcolor.
Stillcolor is super easy to use, just download the app, drop it into your /Applications folder, and launch it. Drop down the menu and choose “Disable Dithering”, and then use your Mac as usual.
If you notice a benefit from Stillcolor, you’ll probably want to enable the ‘Launch at Login’ option in the same dropdown menu.
For those Mac users who are sensitive to temporal dithering, they might report noticeable improvements after disabling this feature. Some users of the LED screen Mac series like the MacBook Pro have noted particular benefit, but those who use the LCD screen series like MacBook Air and MacBook Neo could theoretically have a benefit too.
There are some theoretical downsides to disabling temporal dithering, including reduced color depth and more visible color banding, less smooth gradient transitions, and maybe even slightly reduced image fidelity, so if you’re graphic designer, photo editor, video editor, or doing any sort of professional level image or video work, this may not be an acceptable trade-off. And remember, simply disabling dithering will not disable PWM, which is usually a more problematic flicker for sensitive users.
Is Stillcolor right for you? That’s hard to say, as every user is different, but if you have experienced inexplicable eye strain or eye fatigue, headaches, discomfort, nausea, headaches, or general weird feelings in the eyes or head while using a computer recently, that you used to not experience, this could be a part of that, and the Stillcolor tool could help. It’s a free download that’s super easy to use, and there isn’t much downside to trying it out for anyone who isn’t a professional working with media. This is a niche tool, admittedly, since the negative effects of dithering are really only experienced by a relatively small subset of users. (And BTW, dithering is not unique to the Mac, many Windows PC’s have PWM and dithering too).
For what it’s worth, I personally am sensitive to PWM, and it turns out, I am also sensitive to Temporal Dithering. While the flickering is imperceptible to most users, it’s quite noticeable to me, especially on the PWM heavy OLED iPhone displays and OLED iPad Pro models. I also notice it on the newer model MacBook Pro with LED backlighting, which I simply can’t use, and I make sure to always personally use and buy the LCD display MacBook Air models, and I always use an LCD external display as well. While there are not a ton of us who have issues with these display flickering features, if they do impact you, it’s not a fun experience since they can cause strain and fatigue when using a computer.
And yes this does certainly feel like an accessibility issue, so hopefully Apple will eventually implement features directly in MacOS, iOS, and ipadOS, to disable PWM directly, and dithering as well, natively as part of an Display Accessibility feature. In the meantime, try out Stillcolor on your Mac, and my personal choice has been to only use LCD displays whenever possible. There’s also a petition for Apple to address these issues, though it hasn’t garnered much publicity.
You can read more about the Stillcolor app at the Github project page here, or the developers detailed LEDstrain forum post here.
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Are you impacted by PWM or dithering? Have you tried Stillcolor for disabling temporal dithering on the Mac? Did it reduce eye strain or change how your display looks or feels to you? Share your experience in the comments below, with Stillcolor and any related display or eye fatigue issues with Mac usage, we’re curious to hear from you!
