Over recent years, an unseen occurrence has been affecting the multitude of pixels comprising our screens. Initially intended to address a specific issue, temporal dithering has spawned its own significant problem that is gradually impacting both new and older devices, making them unusable for a segment of the population, and Android users are voicing their frustrations.
On July 9, a formal bug report was submitted to Google’s Android issue tracker, detailing how system-wide temporal dithering was adversely impacting users. The issues resonate strongly with an article I penned over two years ago regarding how the flickering caused by PWM dimming was inducing headaches and nausea.
However, in contrast to PWM dimming, temporal dithering can be implemented on a device well after its purchase, sometimes years down the line. Apple’s iPhones rank among the primary culprits of this practice, compelling users to seek methods to “downgrade” to an earlier iOS version (frequently iOS 17) to avoid debilitating problems.
Numerous Android phones are also to blame, and while Android users enjoy a significantly broader selection than what Apple offers, the roster of phones that are certified flicker-free and those that do not utilize temporal dithering has diminished to almost nothing. It is crucial for Google to invest in new accessibility features to assist a substantial group of users from needing to abandon smartphones entirely.
What is temporal dithering?
Displays typically consist of millions of pixels, each individually rendering colors that form the visuals we observe on our devices. To generate these colors, pixels modify the hue of their red, green, or blue subpixels. It’s akin to Bob Ross dipping his brush into crimson red and azure blue to concoct a beautiful shade of purple for a sunset scene.
Temporal dithering, also referred to as FRC or Frame Rate Control, operates differently. Rather than simply presenting a fixed set of colors to create a single hue, temporal dithering alternates subpixels between colors rapidly to produce a color that essentially does not exist. The human eye perceives this “new” color due to the mechanics of vision. If something is flashed quickly enough before your eyes, it begins to register as a solid or moving image rather than a series of flickering frames.
This clever engineering tactic conserves research and development expenses for companies, enabling them to utilize less expensive panels while still claiming their devices exhibit “billions of colors,” even if they technically do not. Unfortunately, similar to PWM dimming, displaying a flashing light or color can lead to headaches, nausea, or in extreme cases, seizures for some individuals.
Avoiding it is nearly impossible
Individuals sensitive to temporal dithering face substantial challenges in locating suitable devices for three primary reasons. Firstly, some monitor manufacturers readily disclose FRC in their specifications, whereas smartphone manufacturers do not.
Consequently, the only methods to ascertain whether a phone or tablet employs dithering are through personal experience of symptoms or finding a review that thoroughly examines the display. I strive to incorporate this information in any review I publish, but as just one person, the sheer number of devices makes comprehensive testing impractical.
Apart from identifying the presence of flickering itself, there is no documented rate at which these pixels flicker. With PWM dimming, most manufacturers now promote information regarding its existence and the dimming rate. Phones from brands like Samsung Galaxy and Google Pixel operate at a slow 240-480Hz, while brands such as OnePlus and Honor raise that figure to between 2160Hz and 4320Hz. A higher rate is preferable for human sensitivity.
The flicker rate of pixels when temporal dithering is utilized remains unknown, aside from the engineering teams that develop the algorithms. As a result, there’s no means to determine which phones have a “safe” flicker rate and which could be problematic for users. All that is evident is that when phones employ temporal dithering, certain users endure genuine discomfort and cannot utilize those devices.
Finally, there are no specific colors, applications, or activities on the phone that could trigger temporal dithering to activate. Some companies may implement temporal dithering around text edges to achieve smoother or more “readable” text, while others might utilize it to enhance animations for a more visually appealing look. It’s a haphazard mix, complicating the search for the right phone, especially for those sensitive to these effects!
If you’d like to conduct your own testing, I suggest this $20 smartphone microscope available on Amazon. Look for a phone capable of at least 240FPS slow-motion video capture — I recommend the OnePlus 12 or OnePlus 13, as both can capture at 480FPS slow motion — and examine various screen sections with the microscope.
I frequently test around text edges and on various icons on the home screen.
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