jordan I think there's more going on with MacOS.

My current theory as to what's going on with macOS:

  • There is definitely some OS-level contrast/edge enhancement going on — including exaggerated colored fringes that are used to create a depth perception effect (see my past few posts for some info about this).

    Windows 10 22H2 and later cause similar-looking "additional" issues on some mostly newer hardware (i.e. older Windows versions might already have issues on that hardware, but 22H2 noticeably makes color fringes even more visible)

  • More relevant to black & white e-ink, I'm also pretty sure that even in a monochrome output, the OS slightly blurs the pixels to the left and right of vertical edges, and possibly even adds very subtle "drop shadows" to every contrasting area. Sometimes I even feel like I can see extra drop shadows for a split second when quickly switching between a dark and bright page, which I don't notice as much on "safe" setups.

  • I tested the above by setting my 2009 MacBook Pro to display only green pixels through the color profile. I verified with a macro camera that the red and blue pixels were entirely off.

    When running Ubuntu 18.04, limiting everything to shades of green gave me PERFECT screen output, the display now being "physically" monochrome actually mitigated my remaining symptoms with the PWM backlight + pixel inversion — literally the most comfortable (monochrome) backlit screen I've used yet.

    On the other hand, when the same latop was running macOS (Monterey), I still had some issues… first thing I noticed is that it still seemed like parts of the screen were "glowing". I am very confident at this point that macOS is adding both "softened edges" and "brightened sharp edges" even in monochrome color output — and this is in addition to the color fringes I previously noticed. This is NOT RELATED to text rendering because it affects the entire screen including graphics.

Extra info for those interested:

Note that the situation with my 2009 13" MBP is actually pretty rare, as most MacBooks also have color issues at the panel level too — for example, a Late 2008 15" MBP I tried (with very similar hardware and GPU!) still causes "macOS-like" issues even with the same Linux hard drive — and (unlike the 2009) I still get strain and see "glowing" when I set the 2008 to green pixels only.

But the 2009 is unique because it's safe on Linux but not macOS.

Because of this, prior to this 2009 MBP, I wasn't able to tell which issues came from macOS vs. the GPU/hardware. Now I finally have evidence that modern macOS itself (even on an ancient laptop that's safe on Linux, and not officially supported by Apple) can cause issues.

Interestingly, the (better) 2009 actually has much MORE intense PWM and pixel inversion compared to the 2008, and even has a more vibrant color gamut… so this seems to confirm that these kinds of issues are caused by some kind of "enhancement" to edges/contrast/subpixels and NOT flicker(!!)

Both laptops support disabling temporal dithering in both OSes.

I REALLY want to investigate a lossless HDMI capture of even just a single macOS frame (with an RGB EDID to rule out the YCbCr issues) that includes some sharp edges on screen — pretty sure most issues aren't even coming the dithering motion, but from the actual color output. Unfortunately I don't have a lossless capture card myself, but if anyone here has one and a MacBook, let me know

      DisplaysShouldNotBeTVs Interesting. Remember that oses can to some extent use different timings as well. Tried to experiment with reduced blanking on a screen, but it ended up with ghosting. It's the black bars you see on slow lotion video. A bit time consuming to experiment with, but it would be interesting to see how timings affects the reading on Opple LightMaster.

      I'm also really interested in seeing some lossless capture. Especially if there is also a screen recording or screenshot of the same picture. With the ScreenCaptureKit update it would be possible to capture true lossless before the other stuff is added for comparison.

        Interesting. I suspect it is either the front light that flickers and causes problems or then something completely else than the display. That display has 15Hz refresh, so 15hz flicker and that is so slow rate that it is hard to believe that it would cause any issues.

        I'm unable to use one of my Kindle Paperwhites whit the light on, as the light flickers and causes eye strain, but I have zero problems reading it with ambient or external light.

          DisplaysShouldNotBeTVs yeah I think there's definitely something going on even with eink from the OS like you were mentioning. Is there a list of window builds that are comfortable for you that you can share?

          That's interesting with the other things too. I remember I use to do online school work on a older iMac core 2 duo, I think it was ccfl as it had the yellow LCD tint issue. I don't remember that causing me issues on that old OSX version. With the darkening around windows and such wasn't that something you or someone else was able to disable btw ?

          The epiphan dvi2pcie can be bought super cheap on eBay, just need to buy a pcie bracket which I can link you one that fits. It has edid emulation too. It's a lossless 1080p capture card. I think that's the one @JTL uses too.

          Epiphan also makes a av.io 4k which supports 4k 30fps lossless and is USB instead of pcie. Has an HDMI port too.

              Maxx this was using it with the backlight off. I had two incandescent lamps on the sides lighting it up. In windows it says the display is 40Hz, I find it best on Text mode which is more black and white instead of grays which could possibly be why? Maybe it dithers with the gray colors?

              When I do full refresh with the clear button I always close my eyes btw

                jordan The epiphan dvi2pcie can be bought super cheap on eBay, just need to buy a pcie bracket which I can link you one that fits. It has edid emulation too. It's a lossless 1080p capture card. I think that's the one @JTL uses too.

                That is correct.

                Epiphan also makes a av.io 4k which supports 4k 30fps lossless and is USB instead of pcie. Has an HDMI port too.

                I would stick to a desktop with PCIe, less chance of issues.

                  jordan With the darkening around windows and such wasn't that something you or someone else was able to disable btw

                  I'm not referring to window shadows (those can be disabled with yabai on macOS) and also NOT referring to text rendering

                  I'm referring to literally seeing "additional" -- as in not visible in screenshots -- very subtle shadows around every object including words (even if the words are part of a photo and not rendered by the OS), other objects in photos, and even single-pixel vertical lines

                  For an example, this Intel driver update in 2013 caused similar issues on the ThinkPad x220 (but in that case, it was caused by the driver and not OS-level…). See the top image for exactly what I mean with the "vertical lines with extra blurry shadows + fringing to the left/right", and the bottom image for what it "should" look like.

                  https://imgur.com/a/hdvlU

                  Note that in a forum post about that similar issue, they also mention these "extra" shadows are visible on all elements, including photos, and not just text.

                  They also mention "red ghosting on the right edge of black pixels" which is exactly what I've noticed on nearly every device/configuration that's unusable to me.

                  https://community.intel.com/t5/Graphics/HD-3000-driver-forced-subpixel-antialising-after-update-to-9-x/m-p/359835

                      DisplaysShouldNotBeTVs oh wow yeah I can definitely see that! I think I remember seeing this in another post recently. Is this something that can be found in any of the dev PDFs for Intel products that has an option to turn off? Wouldn't this be something that is enabled on every GPU driver nowadays?

                      I wonder what computer/software combo produces the most basic flat image 🤔
                      Pre 2013 stuff? I wouldn't mind putting together an old PC or laptop if it is definitely considered safe against this visual trickery

                          jordan I wonder what computer/software combo produces the most basic flat image

                          EDIT: see my next post, I've now achieved an even better result than this by using a similar strategy on my most usable Windows laptop!

                          The flattest image + most readable text I've achieved is on a (heavily configured) 2009 13" MacBook Pro that I've been mentioning (panel LTN133AT09)…

                          specifically when running it with Ubuntu 18.04, nouveau GPU drivers, MATE desktop environment with compositor disabled, dithering disabled, and most importantly fully monochromatic color output (not just grayscale… I used xcalib to disable red and blue subpixels entirely and ONLY use green, the color that's supposed to focus closest to depth of the display).

                          The panel still shows (significant) PWM and pixel inversion, but surprisingly the monochrome green noticeably reduced that PWM "headache" feeling (and the subtle remaning "depth") -- this also roughly lines up with how some here mention that old monochrome CRTs are more comfortable compared to color CRTs.

                          The final piece was a matte screen protector that made pixel inversion unnoticeable (reccomended but optional, since I was already reading perfectly after the monochrome green step.)

                          I am using RealVNC Client to connect to my modern Mac since it is fully lossless unlike NoMachine. (Aside from the screen I made many tweaks to trackpad config, to make it feel much closer to macOS)

                          Note that I feel very tired and can't think clearly under flickering LED lightbulbs, and get a headache from CRTs as well, but after these steps I actually can tolerate this laptop's PWM!

                          In fact I think this is the first device that is actually helping me start building a real tolerance for PWM (which patching didn't do for me at all). After using it I notice that I feel better in PWM-lit rooms and am actually able to keep my eyes wide open for much longer and focus noticeably more consistently in the real world, which I've actually never had a screen help for me before.

                          If you really need a way to work with text on a screen for hours without brain fog, are okay with monochrome, and don't get serious (seizure etc) symptoms from being in a PWM-lit room (even if you still feel really bad when you're in one), I actually recommend this laptop + specific configuration.

                          This is the first setup that has truly felt like a huge step up for me and "totally different" from everything else.

                          I bought this laptop in great condition for under $50 BTW, so it's not a huge investment either!

                          Outside of VNC, with a RAM + SSD upgrade it's still "capable enough" for modern web browsing by itself too.

                          (However, to this day, my 2004 Nintendo DS is the only COLOR display that is 100% flat to me without requiring monochrome. I still don't know why.)

                          Important: even though this all works great on Ubuntu, I still feel blurriness with same green strategy and dithering disabled running native MacOS, so Linux is neccessary.

                          In addition, on many displays I still notice red and blue ghosting trails even if only physically green pixels are lit, possibly due to the type of backlight or LCD overdrive. I'm pretty sure what makes this 2009 unique is that in "green mode" I literally don't percieve ANY other colors at all, even when scrolling it's ONLY green to my eyes.

                          Also, an older Late 2008 15" MBP I tried the exact same steps on still felt blurry and strained me, more than even macOS on the 2009 does, which was shocking because the Late 2008 actually has much less PWM!

                          So it really is EXACTLY the 2009 13" MacBook Pro where this strategy works.

                          Text was fully in focus over 95% of the time while typing on this setup.

                              7 days later

                              DisplaysShouldNotBeTVs

                              @jordan I just managed to create an even flatter image than this on my 2012 Lenovo Yoga 13 (which, BTW, is still my most comfortable and reliable screen EVER)

                              I'm using NegativeScreen app on Windows 8.1 to turn the entire screen into only red subpixels, which has the same effect of simulating a "physically monochrome LCD with no RGB subpixels".

                              Similar to the 2009 MBP — and unlike when I try this same "physically monochrome" idea on other modern screens — I don't feel like I "see different colors in the ghosting trails". This seems to indicate which screens work with this!

                              In addition, red works great on the 2012 Lenovo for me because it doesn't feel harsh like red on most screens. The config file can also be edited to make it green instead.

                              Interestingly, not sure why, but reducing to only red subpixels seems to basically solve the issue with this laptop screen feeling more unstable whenever power or USB accessories are connected! Now I don't notice much difference at all regardless of what's connected — the screen feels pretty stable all the time — which is great.

                              Now, it's even better than the 2009 MBP, because the panel in this laptop also has the advantage of being much more "PWM safe".

                              The 2009 MBP has strobe-like PWM even at max brightness, so even though I was able to create a very stable/usable image on it and don't get "modern screen" issues like brain fog or trouble reading, if I use it for a while I do still end up getting that classic "PWM headache" similar to looking at a CRT for too long, which isn't great.

                              The rendered image still looks very clean and readable (on Linux) so I'm pretty sure this is directly related to PWM.

                              On the other hand, the 2012 Lenovo still has "some form" of PWM, but it's only the "minor brightness dip on every frame" type. For me, I get ZERO eye strain from this laptop even after eleven years of using it (as long as it's on Windows 8.1, at least).

                              The only issue with the Lenovo was sometimes feeling slight nausea or unstable feeling (but not eye strain). However, it has always been my most comfortable screen despite this, since it works very consistently for me ALL the time no matter how I feel, which I can't say about any other device (…aside from the 2004 Nintendo DS).

                              Now, reducing it to only red pixels SOLVED those few remaining issues, the slight disorientation is finally gone, and now I can fully say that this is the best laptop screen of all time.

                                dev