My Rollback to iOS 18

[turbineseaplane]

@AshX

What an informative and detailed description of the dithering issues, thank you so much!

A. You really have my sympathies. A tech issue like this can literally be life altering (in a negative way) and I don't think it's fully appreciated by anyone not going through it, or something like it.

B. You mentioned OLEDs can possibly mitigate this due to being closer to 10 bit. I wonder if that's why this isn't bothering me, and/or why I find it some comfortable on my eyes with my OLED. I also run a HUGE OLED (65") many feet away, and for a while now.

C. Were older Mac devices and screens/OSes better in this regard?

D. I hope you can find something that works. Is this not an issue as much on other OS options?

 

[Cape Dave]

This has been the trend since Apple Silicon, and earlier, OLED. It’s a deep dive, but Apple has been resorting to spatiotemporal dithering via the Apple Silicon GPU to push 10-bit color AKA “P3 wide color” on all their devices. MacOS has been 10-bit for a while now, but pre-Apple Silicon certain GPU and hardware combinations wouldn’t apply dithering as often. Now, it is constant.

It wouldn’t be a problem if the displays were true 10-bit like the Pro Display XDR, but every MacBook and iPad is 8-bit. So we have the fun of FRC (a form of temporal dithering) being applied by the panel itself via the TCON which you cannot affect via user space because it is encrypted and locked. Some users get around this by using a true 8-bit external monitor. OLED seems less affected by this because the panels are closer to 10-bit, but unfortunately PWM is the norm here, so you’re still getting flicker.
So why does this matter? Apple’s dithering algorithm is introducing a 15Hz flicker over 4 frames per refresh cycle on a 60Hz display. It’s even worse on 120Hz. This is a really, really low flicker that is within the medically established risk for seizures, approximately 15-30Hz. Epileptics are encouraged to use high refresh rate screens (higher than 100Hz), so it’s wild that Apple is utilizing this with no accessibility option to disable it. FRC is a little higher at about 30Hz, on average, so still low.

Dithering isn’t *always* on depending on when the GPU or TCON is telling the device to dither. This is why some users say they update iOS or MacOS and suddenly they’re having headaches or migraines or even seizures. They revert to their old OS version and they’re fine. We’ve seen this play out for years. Apple has even introduced it into sub versions of an iOS generation - say iOS 1X.3 for example - which further proves it is a command that can be disabled. Stillcolor is a program made to disable GPU dithering on Apple Silicon Macs, check out this video showing it in real time:

Liquid Glass is likely engaging the dithering algorithm almost constantly, like Mac has, in order to render the UI. It’s the only thing that makes sense, coupled with the animations, transitions, and translucent scheme. Even if you’re not flicker sensitive, it’s hard on the eyes just from the lack of stable contrast alone. This is going to be even worse on LCD devices because they need to utilize more software tricks to render the wide color gamut as they are all 8-bit.

There’s a lot more going on we still have to analyze, but these are the most aggravating variables from what I’ve identified.

Yeah, Apple talks the accessibility talk, but certainly does not walk the accessibility walk. Once again, sad and pathetic, Apple.

 

[I7guy]

I bought the latest iPhone every year for years, but I haven't upgraded since the iPhone 15 PM.
Now I'm selling the iPhone with iOS 26 and enjoying a fresh iPhone 15 PM.

I'll also skip the iPhone 17 PM, as the iPhone 15 PM is more than good enough.

Let's see where Apple's Liquid Glass takes us.

I don't like the animations, the battery doesn't last as long, and the iPhone sometimes gets noticeably warm with the same usage.

Apple probably wanted the new iPhones to feel newer and better by making major changes to iOS and thus boosting sales.

Yep. I have iOS 26 on my iPhone 15PM and like the updates. Probably upgrade my iPhone 14PM to an iOS 17pm in December.

Apple doesn’t care if you buy a phone every year or not. They are not going to change because of what people claim on an online forum. What drives unwanted behavior is sales.

 

[I7guy]

[…]

Apple could largely resolve this by adding options to disable GPU dithering system wide like the program Stillcolor does on MacOS, and by allowing users to disable Liquid Glass and instead use lower powered themes and UI, like on iOS 18 and versions before. This is a solvable problem, but as many of us who have been asking for Accessibility options to disable PWM and dithering the past 5 years can attest, Apple refuses to acknowledge the problem, yet alone solve it. The PWM smoothing feature was a nice attempt, but you can’t smooth out 480Hz PWM with 99% modulation depth.

I do not think Apple ignores anything. They are big on health and accessibility. A more probable explanation is they need to get to an implementation that they are happy with.

And that could take literal years.

 

[Sami13496]

I wish I could go back to iOS 18. Even though the graphical appearance of iOS 26 has gone downhill compared to iOS 18, that’s not as big of a problem for me as all the usability issues the iOS 26 changes introduced. For example, they completely messed up the Safari tab controls, which is downright infuriating. I’ve never been this annoyed using iOS before. We’ve come a long way from the original idea that iOS should be straightforward and a joy to use.

 

[djcerla]

There’s no difference. I got used to the new look and ergonomy in a couple of days, and it’s all the same.

 

[klasma]

We don’t live in the past. Come to the future.

The future is just the future past.

 

[tomtattoo]

If you care that much for appearance and how your phone look, maybe you should consider switching to an Android phone.

Everyone should care about the appearance because 1. it is an iPhone and 2. we pay a bunch of hard earned money for it.

 

[aespana]

Same. Luckily (I guess?) for us they don't make any new Mini phones (or anything like it), so we aren't missing out on any hardware by staying on iOS 18.

I see no reason at all to downgrade to the 26 experience.

Yeah, it's a pro and a con to not see more Minis in the future :´)

Exactly my situation and position. I fear it also will impact the performance gravely.

And it will. Knowing Apple you know that a new version of iOS always affect the performance of older devices. This time there is the ugly UI and also, worst performance.. No thank you

You can still buy old stock of iPhone 16 with iOS 18. It can extend a bit.

Yeah, that's a good option but sadly, I'm not in the US so, the second hand market here is horrible

 

[FatLouie]

@AshX

Thank you for the explanation about dithering, and for recommending Stillcolor. I applied Stillcolor earlier, and my eyes feel a bit better already. 👍

Unless Apple gets on board with the slew of people with vision issues, and fixes this monstrosity called Liquid Glass, and the dithering issue, I can no longer buy Apple devices. I have been looking at OnePlus as a start, trying hard to avoid Samsung.

 

[scrapesleon]

alright y'all over doing this iOS 26 complaining the design is fine get used to it and stop making these silly post

 

[aespana]

alright y'all over doing this iOS 26 complaining the design is fine get used to it and stop making these silly post

Nah, I think that the fail with iOS 26 is so big, we will rant about it for a long time.

I don’t see how Apple can fix this with future updates. Maybe a switch to deactivate the Liquid Glass? I don’t know.. I just don’t want to use it and even less knowing that Apple won’t let you downgrade your iOS version.. oh, how I wish to be in iOS 16 or 17.. even 15, the original for my 13 Mini. It would fly with that version

 

[AshX]

@AshX

What an informative and detailed description of the dithering issues, thank you so much!

A. You really have my sympathies. A tech issue like this can literally be life altering (in a negative way) and I don't think it's fully appreciated by anyone not going through it, or something like it.

B. You mentioned OLEDs can possibly mitigate this due to being closer to 10 bit. I wonder if that's why this isn't bothering me, and/or why I find it some comfortable on my eyes with my OLED. I also run a HUGE OLED (65") many feet away, and for a while now.

C. Were older Mac devices and screens/OSes better in this regard?

D. I hope you can find something that works. Is this not an issue as much on other OS options?

A. Thank you. To say it has completely derailed my career in the last 16 months would be an understatement. I did not have an issue with screens or lighting until I got COVID in 2022. It wasn’t until I got reinfected in 2024 that issues became extreme.

B. There are a lot of theories as to why OLED might be better. The problem I see with discussions about screen sensitivity is often it’s framed as if the issues such as PWM or dithering are mutually exclusive. They’re not.

I prefer to focus on flicker as a whole, specifically frequency and modulation depth. For example, I can use my OLED iPhone 13 from 2021 on iOS 15 all day with minimal issues. But when I tested it against every iPhone 13 in the Apple Store that was released in 2023 side by side, I could not use any of them. So it was likely a combination of the new panels for that model and iOS 16/17.

As to why your OLED is tolerable, it is likely because it is more likely to be 10-bit. It’s also likely that because OLED response times are very fast in most cases, you’re not going to get smearing and artifacts like you would on say the MiniLED MacBook Pros which have worse response times than the older LCD Retina Macs. And because iPhones are OLED, it’s probably fair to assume they will be dithering less often than say an iPhone 11, which is 8-bit and will need to use way more tricks to render the colors and graphics on iOS 18 or 26.

C. Once MacOS went 10-bit (I believe this happened a few OS’s before Big Sur, but I believe Big Sur was when the design teams for iOS, iPadOS, and MacOS were unified. The design language is very similar now) it definitely got worse.

Older Intel Macs were largely dependent on a few variables:

• GPU (Intel or AMD)
• Processor
• Panel type like TN or IPS, plus Apple specific designs (Retina, non-Retina, Liquid Retina, etc)
• Backlight (CCFL, edgelit LED, etc)
• TCON (how often the panel will use FRC to dither)

For example, my 2019 iMac 21.5-in 4K Retina could toggle between 8-bit and 10-bit (millions and billions of colors) using SwitchResX. It helped take the brunt off the dithering on that machine and let me use it after my first COVID infection. But some flickering still remained, despite it being on Mojave.

Some have been able to disable it via terminal commands, but because of the variance in models, processors, OS, and so on its hit or miss. Stillcolor disables GPU dithering but not TCON FRC which is controlled by firmware not accessible via user space. So all the Apple Silicon Macs still dither even if you disable GPU dithering.

D. I haven’t used Windows since I was a kid. Windows 11 is apparently very problematic. The entire industry is shifting to P3 color, so more and more devices are dithering. Every laptop I know to exist is 8-bit + FRC, not true 10-bit. I know people swore by certain instances of Windows 10.

This is the problem. Dithering can be enabled via an OS update. Apps like Photoshop can force dithering to be enabled and even override Stillcolor.

What I think needs to happen is users need to be given control. There should be an Accessibility option to disable it if it affects your health. I don’t think that would take much, after all Stillcolor just alters one command: enableDither=no. So the talk of Apple needing time to implement it just isn’t true. They could equally send a command to the panel’s TCON to disable FRC. At the very least this, plus offering PWM free, flicker free devices, would give people who have neurological and visual disabilities - as well as those who are health conscious or would prefer not to look at the equivalent of a strobe light all day - an option.

That’s all I’ve been asking for, and I’ve been speaking to journalists about this. Myself and many other long COVID “long haulers” plus others with health conditions have been affected by this for years. It’s not the 1960s - you need a phone and a computer to function in careers and society. They’re not a luxury. My banking apps aren’t even working on iOS 15 anymore. So my choice is update to iOS 26 and lose access to the only screen I can even look at. It’s not a choice at all.

We will look back at this in 10 years and go what were we thinking regarding flickering LEDs and screens. I may be one of the most severely affected individuals, but as a top NYC ophthalmologist told me, everyone is affected, they just dismiss it as blue light or screen time. It’s not.

 

[AshX]

Thank you for the detailed explanations, especially regarding the problems sensitive people have with PWM and so on.

I'm not that sensitive to PWM, but with iOS26, my eyes are more tired after a day than they were with iOS18.
Unfortunately, I also have iPad OS26 installed on my iPad Pro, but I won't be switching to a new iPad Pro with iOS18 because I don't use the device much compared to my iPhone, and I really hope that Apple will at least let users turn off the exaggerated glass effects.
Apart from the skewed app icons and borders, there are enough areas for Apple to work on with iOS26.

However, if Apple sticks with Liquid Glass, switching to Samsung would still be an option, even though I'm not an Android fan, but Samsung's One UI 8 is really nice to look at.

One of the tell-tale signs of dithering is a difficulty focusing on text. PWM can also cause this but if you have a PWM free display it’s easier to isolate. The eyes are constantly trying to re-focus as the dither pattern repeats.

Yeah, Apple talks the accessibility talk, but certainly does not walk the accessibility walk. Once again, sad and pathetic, Apple.

It is strange that they will release an accessibility option to dim the screen on Macs when strobe lights appear on screen for epileptics, yet as the screen dims the PWM modulation goes out of control. Ironic.

I do not think Apple ignores anything. They are big on health and accessibility. A more probable explanation is they need to get to an implementation that they are happy with.

And that could take literal years.

Stillcolor’s command is literally “enableDither=no.” It’s not hard. Apple is ignoring it because they were sued in 2007 for dithering to fake 8-bit: https://www.theregister.com/2007/05/21/apple_display_lawsuit/

Most of their devices can’t reproduce 10-bit color natively. They need to dither to accomplish this - or “fake” it. Fine, but give us an option to disable it. And be honest like other monitor manufacturers are when they indicate a monitor is 8-bit+FRC or true 10-bit instead of obfuscating behind “supports billions of colors.”

 

[I7guy]

Stillcolor’s command is literally “enableDither=no.” It’s not hard. Apple is ignoring it because they were sued in 2007 for dithering to fake 8-bit: https://www.theregister.com/2007/05/21/apple_display_lawsuit/

Most of their devices can’t reproduce 10-bit color natively. They need to dither to accomplish this - or “fake” it. Fine, but give us an option to disable it. And be honest like other monitor manufacturers are when they indicate a monitor is 8-bit+FRC or true 10-bit instead of obfuscating behind “supports billions of colors.”

We do have some parallels and I do empathize with those who have health issues. I have been diagnosed with long covid and have seen a top neuro-ophthalmologist at Columbia Presbyterian for vision issues that are still currently undiagnosed. (One difference is im entrenched in windows and not Mac)

Even with my vision issues modern Apple displays don’t give me headaches and overall I like Liquid Glass and iOS 26.

As far as the lawsuit the article didn’t mention the outcome. Suing is easy and winning is harder.

Also OP seems to edited their posts and removed all verbiage.

 

[turbineseaplane]

Most of their devices can’t reproduce 10-bit color natively. They need to dither to accomplish this - or “fake” it. Fine, but give us an option to disable it. And be honest like other monitor manufacturers are when they indicate a monitor is 8-bit+FRC or true 10-bit instead of obfuscating behind “supports billions of colors.”

I totally agree and wish Apple would be on the level about this.

It’s far too important to just bury underneath marketing speak.

 

[winxmac]

Also OP seems to edited their posts and removed all verbiage.

I also noticed that. Why did you clear the post @Crowlover0815 ?

 

[AshX]

We do have some parallels and I do empathize with those who have health issues. I have been diagnosed with long covid and have seen a top neuro-ophthalmologist at Columbia Presbyterian for vision issues that are still currently undiagnosed. (One difference is im entrenched in windows and not Mac)

Even with my vision issues modern Apple displays don’t give me headaches and overall I like Liquid Glass and iOS 26.

As far as the lawsuit the article didn’t mention the outcome. Suing is easy and winning is harder.

Also OP seems to edited their posts and removed all verbiage.

I’m sorry to hear that you are also suffering with long COVID. I was diagnosed with binocular vision dysfunction and photophobia as a formality, but the neuro-ophthalmologist I saw at SUNY emphasized COVID was what had triggered all this and no one knows what is going on.

In retrospect, I remember finding the iMac Pro very uncomfortable to use in 2018. It was likely the 200Hz PWM. I do believe the shift in backlight design, font rendering, and dithering is the major trigger.

Very odd OP edited everything. I know topics like these are very unpopular on Apple forums. For whatever reason people would rather attack, shame, and blame users who have visual and neurological reactions to Apple screens over the past 5-7 years. Apple Support forums are rife with them.

I will just say, I would not wish these problems on my worst enemy. But for those who think this can be hand-waved away: I did not have problems at all before my COVID infection. So it can happen to anyone and I would implore folks to have empathy and support the push for simple accessibility toggles. No one is trying to take away your Liquid Glass or dithering or PWM if you like it. We would just like the option to disable those features within settings, the same as other accessibility options that limit a device’s display output. It’s that simple and I don’t know why it’s so controversial.

I totally agree and wish Apple would be on the level about this.

It’s far too important to just bury underneath marketing speak.

People have been suffering for years. There is growing talk among users in North America and Europe about filing a class action lawsuit on the basis of health. We have tried everything from support tickets, petitions, speaking to store and regional managers, reaching out to developers and upper management. All we get is crickets.

I thought health was a priority for Apple and being inclusive to those with disabilities they did not ask to have. But I suppose it doesn’t matter so long as they can meet display brightness, color, and battery life benchmarks, even if that means under-volting their displays and introducing unwanted flicker (or wanted in the case of dithering) that affects people’s health.

 

[schneeland]

I didn't have the need to downgrade, because I'm generally conservative with system updates, but I did have to upgrade my company phone to iOS 26 (because of mobile device management policies), and I was negatively surprised. I was already a bit wary because of screenshots I had seen, but I had assumed that maybe it wouldn't be so bad in practice. Yet, my first thought when I saw it live was: "Well, looks ... kinda crap".
Maybe it's less bad with another wallpaper, but it simply did not strike me as something compelling. Now I don't think I will exit the ecosystem because of it (I generally like my Apple devices), but it does make me reconsider purchasing a new iPad (Pro) in the near future.

 

[scrapesleon]

Nah, I think that the fail with iOS 26 is so big, we will rant about it for a long time.

I don’t see how Apple can fix this with future updates. Maybe a switch to deactivate the Liquid Glass? I don’t know.. I just don’t want to use it and even less knowing that Apple won’t let you downgrade your iOS version.. oh, how I wish to be in iOS 16 or 17.. even 15, the original for my 13 Mini. It would fly with that version

If you were using your devices more you would know by now that every iOS on release has been buggy since iOS 14 but then y'all weren't paying attention to details till now get over it the iOS will start being stable after the .2 updates and the same goes for people using the betas that never report bugs look where it has gotten the iOS now

 

[Heat_Fan89]

I tried iOS 26 but other than the new updated look, which I actually liked, I dropped back down to iOS 18. I have an iPhone 13 and because it doesn't have 8GB of RAM, there's no real benefit other than the new look because it will not support AI. I also noticed a performance hit that gave me flashbacks to iOS 7 on my iPad 2 and iPad 3. I don't think the iPhone 13 will get any better with iOS 27 and other upgrades.

So I really liked the new clear look but the phone runs a lot better with iOS 18.

 

[FeliApple]

If you were using your devices more you would know by now that every iOS on release has been buggy since iOS 14 but then y'all weren't paying attention to details till now get over it the iOS will start being stable after the .2 updates and the same goes for people using the betas that never report bugs look where it has gotten the iOS now

This is not true, and a common myth. It might improve relative to .0, but it will always be worse in terms of battery life AND performance vs original iOS versions.

And the funny thing is, you can pretty much only downgrade during the .0 release.

So I now have to judge a new iOS version on a hypothetical .2 release, while testing the .0 release, and refrain from downgrading because it will get better on that .2 release, from which I CANNOT downgrade?

It is not a logical argument. I can’t miss the downgrade window over a hypothetical and non-existent improvement of a future, unreleased version.

The approach of those who tried the initial release and then downgraded was 100% correct:

I test what I can. I don’t like it, I go back.

It’s not the user’s fault if Apple forces itself into these yearly releases for which it has NO time to beta test. Some users have argued that the beta is alpha and the regular release is beta up to a point.

And this is omitting the fact that final releases are utter garbage. I was forced by Apple to update to the final iOS 12 version from iOS 9 on my 9.7-inch iPad Pro: 25-30% worse battery life and keyboard lag. I was forced by Apple to update to the final iOS 13 release on my 6s from iOS 9: complete garbage, 60% drop in battery life, and a performance disaster. Where was the improvement? Nowhere.

I wish people stopped proliferating this myth. Major updates are malware, on .0 releases and on .7 releases. As you increase the distance from the original version, it gets worse and worse.

 

[turbineseaplane]

It’s not the user’s fault if Apple forces itself into these yearly releases for which it has NO time to beta test. Some users have argued that the beta is alpha and the regular release is beta up to a point.

I really wish they'd stop doing this.

Every single year the forced reset starts a whole new cycle of fresh bugs and issues for exactly ZERO reason or benefit.

 

[I7guy]

This is not true, and a common myth. It might improve relative to .0, but it will always be worse in terms of battery life AND performance vs original iOS versions.

I actually don’t care that battery life is worse because functionally the latest release is better. Battery life being worse means nothing with myriad of ways to charge a phone in 2025.

And the funny thing is, you can pretty much only downgrade during the .0 release.

Been like that for quite some time.

So I now have to judge a new iOS version on a hypothetical .2 release, while testing the .0 release, and refrain from downgrading because it will get better on that .2 release, from which I CANNOT downgrade?

You don’t have to upgrade and can wait as long as you want. Of course one will kiss the functionality upgrades, but that is the trade off.

It is not a logical argument. I can’t miss the downgrade window over a hypothetical and non-existent improvement of a future, unreleased version.

Sure, then don’t upgrade to the next release.

The approach of those who tried the initial release and then downgraded was 100% correct:

I test what I can. I don’t like it, I go back.

Absolutely. Apple provides that path.

It’s not the user’s fault if Apple forces itself into these yearly releases for which it has NO time to beta test. Some users have argued that the beta is alpha and the regular release is beta up to a point.

It’s not apples fault when Apple comes up with a yearly release with improved functionality and the user doesn’t want to upgrade.

And this is omitting the fact that final releases are utter garbage. I was forced by Apple to update to the final iOS 12 version from iOS 9 on my 9.7-inch iPad Pro: 25-30% worse battery life and keyboard lag. I was forced by Apple to update to the final iOS 13 release on my 6s from iOS 9: complete garbage, 60% drop in battery life, and a performance disaster. Where was the improvement? Nowhere.

Nonsense. One anecdotal upgrade does not make a general case across all models and operating systems.

I wish people stopped proliferating this myth. Major updates are malware, on .0 releases and on .7 releases. As you increase the distance from the original version, it gets worse and worse.

This is blatantly untrue.

 

[ultratiem]

Let´s not forget about these companies which still refuse to offer a proper dark icon for dark mode.
So you have three! different styles on iOS18: no dark icon, iOS 18 icon, iOS26 icon.

And they are talking about "unifying the design all over devices"
It is ridicolous.

When they say unify, they mean cheap out. The fact they made the Music app UI exactly that of the iPad shows just how lost their executives are. Trillion dollars and they slap the touch UI of a tablet on a goddamn desktop or laptop. My Studio is commented to a 27” Studio Display and a 42” OLED. As such, the new UI, and all it’s tiny little windows that bafflingly cannot be resized (or some only vertically, like what?!) on giant ass screens makes macOS feel like it was ,ade by Microsoft (fully insulting).

Apple has completely fallen off the map with OS 26. It legitimately feels like OS 15/18 painted over by some Fiver artists.