Just dropping a quick script here for people that want to experiment with multipe flags a bit easier. Just drop it in an .sh file. It required betterdisplaycli. Do note that some of the values have been found to improve things, and some are just not found to cause adverse effects. If anyone wants to experiment use something like TestUFO.

#!/bin/bash

# Helper function to run command and print specifier
run_and_print() {
    local specifier=$1
    local property_type=$2
    local property_value=$3
    local display_name="built"

    # Get the current value
    local current_value=$(betterdisplaycli get -namelike="$display_name" -specifier="$specifier" -framebuffer"$property_type"Property 2>&1)

    # Set the new value
    local output=$(betterdisplaycli set -namelike="$display_name" -specifier="$specifier" -framebuffer"$property_type"Property="$property_value" 2>&1)

    if [[ $output == *"Failed"* ]]; then
        echo "\033[31m$specifier\033[0m\033[90m - $current_value"
    else
        echo "\033[32m$specifier\033[0m\033[90m - $current_value - $property_value\033[0m"
    fi
}
# Boolean properties
run_and_print "enableDither" "Bool" "off"
run_and_print "uniformity2D" "Bool" "off"
run_and_print "IOMFBTemperatureCompensationEnable" "Bool" "off"
run_and_print "IOMFBBrightnessCompensationEnable" "Bool" "off"
run_and_print "enable2DTemperatureCorrection" "Bool" "off"
run_and_print "enableDarkEnhancer" "Bool" "off"
run_and_print "DisableTempComp" "Bool" "on"

run_and_print "AmbientBrightness" "Numeric" "0"
run_and_print "IOMFBContrastEnhancerStrength" "Numeric" "0" # better to look at with it on but it seems to adjust slowly causing flicker and blotching
run_and_print "IdleCachingMethod" "Numeric" "1" # reduces software cursor flicker from color profile

run_and_print "overdriveCompCutoff" "Numeric" "0" // default 334233600, can cause stuck pixels?
run_and_print "VUCEnable" "Bool" "off" # unstable?

run_and_print "BLMAHMode" "Numeric" "1" # default 2

# stuff that seems a bit better on
#run_and_print "APTEnableCA" "Bool" "on"
# run_and_print "enableBLMSloper" "Bool" "on"
# run_and_print "APTEnablePRC" "Bool" "on"
# run_and_print "APTPDCEnable" "Bool" "on"
# run_and_print "enableDBMMode" "Bool" "on"
# run_and_print "BLMPowergateEnable" "Bool" "on"
# run_and_print "IOMFBSupports2DBL" "Bool" "on"

# run_and_print "DisableDisplayOptimize" "Numeric" "1" # unstable

Donux
Sure, there are some software "algorithms for image improvement" made by Apple that affect image quality - like dithering.

Basic goal is to rate all Macbooks' displays by hardware. Especially for IPS MBA 15'' M3's built-in displays.
For example. We have 3 suppliers (vendors). And in terms of quality. With the same software algorithms ON - one of the displays supplier (vendor) is better then another… Would be great to define which one is better and then to have fast-check Terminal command to define which supplier (vendor) is in each specific MBA 15'' M3 specimen …

If hardware quality of those vendors is very similar and image is practically similar this would be also a good result.
…
Is there only one vendor or several? If several 2, 3 or more then:
IPS MBA 15'' M3 vendors rating
1st place. Best - Vendor's name 1 - vendor's code 1 in Terminal ioreg etc - reason why it is the best one
2nd place. W - Vendor's name 2 - vendor's code 2 in Terminal ioreg etc - reason why it is in the middle
3rd place. Worst - reason why it is in the worst one
…

I've started this research because I am not satisfied with IPS display that my new MBA 15'' M3 has.
Even if
- dithering is OFF
- RGB standard profile is ON in system settings
My MBA 15'' M3 still has
- brightness flickering when pressing F1-F2, it is not changing smoothly
- linear gradients are not smooth, there are some linear effect appears randomly
- black text on white background seems too annoying too much "contrast". It is visible also when system loading and you see white Apple logo on black screen. Same effect

Comparing to my MBP 15'' 2014 where
- brightness changes smoothly and
- gradients also very smooth and stable

So if there is some MBA 15'' M3 with the Best built-in display from vendor (rated as 1st place). The one that has
- smooth brightness changing F1-F2 and
- gradients also very smooth and stable
That would be great to find this "version" of MBA 15'' M3 with better one display supplier

      I use Gamma Control for color adjustments now. And at times there is some type of graphics switch that can be seen as it takes a second or two until those adjustments are applied again. So far I didn't pinpoint exactly what happens happens, but it might be relevant to figure out.

      I noticed it happening in one app when it shows some particular icons, and for this app that I briefly testet it happens upon closing the app. https://apps.apple.com/us/app/almighty-powerful-tweaks/id1576440429?mt=12

      I've noticed these messages, but changing them around thru GlobalPreferences doesn't seep to influence them. However it might be a way to force sRGB output. There is a ton of settings loaded for most apps that can be changed here.

      CAEnableDeepFramebuffer
      CSEnableIOSurfaceCompression
      CADisableColorMatching
      CADisableShadingDither
      FramebufferServerUseLowQualityScaling
      NSDeepDefaultWorkingColorSpace
      NSExtendedWorkingColorSpace
      NSExtendedWorkingColorSpace
      NSLinearWorkingColorSpace
      NSSingleWorkingColorSpace
      NSExtendedWorkingColorSpace
      NSWindowUsesZeroScreenForDefaultColorSpace

      Discovered something interesting. This can be used to affect the rendering of different apps. It can also be applied in the plist for specific apps.

      Setting it to 1 will make apps like Apple Notes blurry, and some uneven values will mess up the text a bit or make it sharper.

      If you play around with it DO NOT try floats, as that will crash the window server even in safe mode, and you will be forced to fix it in single user mode.

      ⚡13% 17:25:29 ➜ defaults -currentHost write -g NSCGSWindowSkylightSupportsMoreScaleFactors -bool yes
      ⚡13% 17:26:00 ➜ defaults -currentHost write -g NSWindowScaleFactor -int 1
      ⚡13% 17:26:13 ➜ defaults -currentHost write -g NSWindowScaleFactor -int 2
      ⚡13% 17:26:30 ➜ defaults -currentHost write -g NSWindowScaleFactor -int 3
      ⚡13% 17:26:38 ➜ defaults -currentHost write -g NSWindowScaleFactor -int 10

      There are also another option named NSTypesetterBehavior that seems to be able to force typography to how it was in previous versions of MacOS https://developer.apple.com/documentation/appkit/nstypesetterbehavior?changes=_4_1&language=objc

        async Played around a bit with this. So if I apply it to for example Chrome

        defaults -currentHost write com.google.Chrome NSCGSWindowSkylightSupportsMoreScaleFactors -bool yes
        defaults -currentHost write com.google.Chrome NSWindowScaleFactor -int 1

        Anything under another window / shadow becomes blurry, and goes into focus again if I switch to the window. But if I have an overlay on the screen then Chrome is sharp until I stop doing something, then after a second or so it all turns blurry. So this is related to idlemode somehow. Also if using any type of overlay they you most likely have a slight shift of everything all the time

        Also I figured out that Kaleidoscope for Mac can be used to diff images to see subtle changes in text rendering, like when turning on and off hardware acceleration.

          Played around with Opple LightMaster IV on my M1 Max. Measured flicker at a frequency of 15006 hz.

          Modulation depth:

          - White 53.1%
          - Black 39.65
          - Red 7.19%
          - Green 76%
          - Blue 79.09%
          - Pink 35,72% (red + blue)
          - Yellow 44.17% (red + green)

          What's up with the modulation depth on red. Did anyone see this? Slow KSF phosphor, or something else going on?

            async Am I correctly understand higher percentage is more flicker? If so, does that mean optimum is up to 5 percent to be classified as flicker-free ?

                Donux It is modulation depth, so 15006 times per second the brightness drops 79% when looking at a pure blue background. The question is why that doesn't happen with red. If this was simply the backlight flicker (not PWM) then at least for me it makes no sense that it doesn't affect red.

                Could it be that KSF phosphor that is slower to respond causes this?

                https://pcmonitors.info/articles/the-evolution-of-led-backlights/

                Just thinking as I type here, and I'm probably butchering the explanation and understanding of the visual system. A lot of how the visual system works it is built around opponency of the following types.

                • High / low luminance (black / white)
                • Red / green
                • Yellow / blue

                Basically our vision detects a shitton of edges and gratengs thru these combos.

                What actually happens if red doesn't flicker (due to KSF phosphor) while green that hit the M and L cones does?**

                We have some rods that mainly respond to brightness (black and white), and we have 3 types of cones that maps to different colors. The type of color and input can make us use certain visual pathways more or less. So looking at large slowly moving black and white blobs will take a different path than looking at colored details.

                Cone cell - Wikipedia

                Some quick info on the 3 pathways:

                Magnocellular (M) pathway:

                • Processes motion, depth, and coarse visual details

                • More sensitive to low spatial frequencies and high temporal frequencies

                • Plays a role in detecting sudden changes or movement

                • Most vulnerable to flicker due to its high temporal resolution

                • Responds strongly to rapid changes in luminance

                • Sensitive to low spatial frequencies and high temporal frequencies

                • Studies have shown M pathway neurons can follow flicker rates up to 60-80 Hz

                Parvocellular (P) pathway:

                • Processes fine detail and color information

                • More sensitive to high spatial frequencies and lower temporal frequencies

                • Important for form and object recognition

                • Less sensitive to flicker compared to M pathway

                • More responsive to steady-state stimuli

                • Can still be affected by flicker, especially at lower frequencies

                • Triggered by red-green opponency.

                Koniocellular (K) pathway:

                • Less well-understood compared to M and P pathways

                • Involved in color processing, particularly blue-yellow distinctions

                • May play a role in eye movement control and visual attention

                • Less well-studied in terms of flicker sensitivity

                • Some evidence suggests it may play a role in processing rapid color changes

                Maybe one of the problems of KSF phosphor is mainly present when there is high frequency flickering, as instead of a simple brightness dip that affects the Magnocellular pathway, you would keep hammering the Parvocellular pathway with edge / no-edge / edge / no-edge. 15000 times pr second.

                Remember that white on the display consists of RGB. So to avoid this you would need to remove either all red resulting in a cyan image, or remove both green and blue resulting in a pure red image. This can be done with Gamma Control if someone wants to experiment.

                One thing to note is that if making blacks brighter or color shifted this effect could be significantly increased, as pure black doesn't generate any signal for yellow-blue opponency. One could also argue that newer screens getting better with less bleeding and overly blue backlight could trigger less of the different types of opponencies that the visual system uses to detect edges.

                Say you want to create the maximum amount of opponency signals for text you would make blacks slightly gray and purple (blue and red), and you would make the whites greenish yellow. The luminance contrast is there in any case. Compared to a perfect screen with pure black and white you would have 3 opponency channels instead of 1. Not necessarily beneficial, but worth thinking about.

                In any case I'm a strong advocate for experimenting with small color shifts the make screens feel better, and I think the differerent flicker rates of the colors for the MacBook display potentially could be the reason it messes up people.

                @DisplaysShouldNotBeTVs

                  async How does the red modulation depth change when you disable IOMFB brightness compensation?

                  /Applications/BetterDisplay.app/Contents/MacOS/BetterDisplay set -namelike=built -framebufferBoolProperty=off -specifier=IOMFBBrightnessCompensationEnable

                  This command creates an immediate effect on M1 Air (not sure about mini-LED) where the backlight becomes noticeably more red and a "little bit more stable"

                  And when turning brightness compensation back on again, even though the backlight looks more blueish again, I immediately notice that there's still a red component but it's slightly flickery

                  So when brightness compensation is on, it's likely that it's done by flickering red subpixels in some way

                  Interestingly, a related experience is on a 2016 MacBook Pro, when in Boot Camp Windows 10 the backlight becomes more red and blue at 10% intervals, 100% is reddish 90% is blueish and so on. When in macOS the backlight temperature stays the same at all brightness levels. So this might be flickering red in order to compensate for the slight color temperature difference with different backlight levels.

                  BTW unlike the M1 Air, the 2016 13" Pro is PWM-free (but I still get some strain + a different set of issues with it)

                  I can notice a similar effect on iPhone 14 Pro. since that's OLED, it's not related to a backlight in that case, but I see the same type of flicker I notice on my M1 Air

                  In addition, if I use PWM-free screens for a while, the slight flickering of red I see in both devices becomes much more noticeable the next time I come back to them

                      DisplaysShouldNotBeTVs I don't see any difference on the display from that one. I've tried a lot, and I can't really find anyone that affects the modulation.

                        async Was this tested with night shift and/or True Tone on? I believe someone here determined that these features are implemented by flickering certain color subpixels.

                            macsforme Nope. I get wrecked by true tone. Would be interesting if someone with opple can check the different solid colors on their high gamut display.

                            One thing is the high frequency flicker, but if the lack of modulation is just the red phosphor and opponency is the problem you would potentially trigger the same type of issue when pwm hits at lower brightness or when scrolling, at a much lower frequency.

                              @async doublecheck did you measure with other equip and test on another one to make sure its a valid observation?

                                6 days later

                                Ivan_P Here are the color filter glasses I use: https://www.amazon.com/GloFX-Color-Therapy-Glasses-Chakra/dp/B073PM1JF1

                                Specifically the red versions. I tried the orange and blue versions and they did nothing for me. And all the other varieties of "blue light blocking" glasses I've tried don't help at all either. But it is specifically these red ones which give me immediate relief that nothing else can.

                                They don't entirely "fix" a screen, but even when I was stuck with the atrocious 14" mini-LED 2021 MacBook Pro (the worst and hardest to read screen EVER) they at least barely got me through work during that time of my life, when previously I couldn't work at all, so they definitely improve things and very consistently too.

                                In addition, they work even better with older screens that "have pretty decent output but still cause eye pain". For example, an old 2014 ASUS T100TA netbook with an AUO panel that does give me eye strain, yet despite that is also uniquely easy for me to read (compared to modern screens where I immediately feel confused while reading) I was able to massively improve with these glasses. Now I can finally use that netbook daily.

                                (For reference, the 2012 IdeaPad Yoga 13 with LP133WD2-SLB1 panel is still the only laptop that I am 100% perfect using "normally", it is fully readable and I get nearly zero strain, with no glasses or other physical workarounds needed at all.)

                                By the way, many times these color filter glasses even help the real world feel more relaxing too for me, sometimes I use them to simply feel more focused and energetic while just getting some chores done etc.

                                I also met someone else IRL with very similar symptoms to me recently, I let them try the glasses, and they said it immediately improved their iPhone 11 which they typically have a lot of problems with.

                                In addition, you can use the NegativeScreen Windows app to filter the screen entirely red, which sometimes works even better in combination with the glasses (some laptops benefit a ton from this, some not at all, YMMV)

                                    DisplaysShouldNotBeTVs thanks for providing such a detailed explanation!

                                    I'll try those glasses and write a feedback when will be ready 🤓

                                      DisplaysShouldNotBeTVs I have a similar red filter glasses and i can feel it kind of makes text easier to read (maybe it helps with my astig?)

                                      one thing i noticed is that if you ever use all red mode + night mode, it helps to filter out the led light at the black area, improving the contrast

                                          dev