OSX dithering - Help wanted
annv I hope more people try it and tell what they feel.
Could you please give a quick step by step of how you used Hackintool in this instance in case others want to try installing with Catalina, and at what point you referred to the official instructions for installation? Thanks, and good luck!
I mounted the disk image (step 1 on page 6)
And then I followed the instructions listed on the page: https://www.tonymacx86.com/threads/guide-installing-3rd-party-kexts-el-capitan-sierra-high-sierra-mojave-catalina.268964/
Starting from the words:
"The Hackintool Method"
and till the words:
"Thats it .. job done ... don't worry that the output is red .. thats completely normal, you should now reboot your system to load the newly installed kexts."
However, instead of that red output I had a message I listed above about system policy. But, as stated in AHK manual, I unblocked the kext in Security and Privacy.
As far as I remember, the kext was listed among loaded kexts even without restarting the computer.
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annv At first, I had this message in Hackertool:
But probably that's because the kext was initially blocked by security in the Security and Privacy section of the Preferences.
I think this may be to do with SIP on modern versions of MacOS. Also I think the kext needs to be signed for Catalina..
For some time now, Apple has required those developing kernel extensions to obtain special security certificates for their KEXTs. In April this year, for Mojave and Catalina, kernel extensions have also had to be notarized, which ensures that Apple has checked each of them for malware as well.
Main security checks therefore have to be performed when you first install a kernel extension. If it was signed from April 2019 onwards but hasn’t been notarized, Mojave and Catalina will refuse to accept it, and although in some circumstances you might be able to work around that (in Mojave at least), in most cases that is and should be a show-stopper. It means the kernel extension hasn’t been checked for malware by Apple, and you simply shouldn’t trust it: contact its developer and remind them of Apple’s security rules.
Even when it has been notarized and passes Catalina’s security checks, you still have to add it using the General tab of the Security & Privacy pane – what Apple terms User-Approved Kernel Extension Loading. Although Catalina tends to bombard you with alerts and prompts when installing and first running some software, this is one of the more important, and needs particular care.
Catalina was to have introduced a further change to the installation of kernel extensions, which required the Mac to restart after the user had approved an extension, before it could be loaded. This was present in most betas, but was removed shortly before 10.15 was released, and it’s unclear whether this applies to the release version, will be re-instated in a future update to Catalina, or has been abandoned altogether. Hopefully Apple will clarify this soon.
Once a kernel extension has been built into the prelinked kernel, the latter needs System Integrity Protection (SIP), to ensure that nothing else can tamper with its contents. In Catalina, that not only means setting permissions and applying SIP, but storing it on the read-only System volume.
Good luck and let us know how it goes 
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I did not restart Mac, so that requirement might have been removed in release version.
I wonder if I can be sure the kext is loaded and active, if it's shown among loaded kexts. I'm unsure because I do not feel much difference yet. For instance, the Safe Boot still looks different.
si_edgey
According to KextViewr info, the kext is third party, but signed (a closed black lock to the left of the kext name)
Yes, it should be loaded.
I guess I need to go for a few days with it.
Just realized I'm working with the text for quite some time and I do not have a feeling of overworked eyes (like sleepy).
Still cannot use the iMac without Gamma Control. The screen is too bright.
si_edgey Sorry to burst your bubble
https://philtechnicalblog.blogspot.com/2013/02/amulets-temporal-dithering-kext-fear-of.html
checking for the presence of Amulet hardware (that's an expensive dongle!);
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JTL Sorry to burst your bubble
https://philtechnicalblog.blogspot.com/2013/02/amulets-temporal-dithering-kext-fear-of.html
On the contrary, this is actually great news because now we know who developed the KEXT. I have tracked him down and am making contact to propose the development of a KEXT for us. I will post updates here as we go on.
tfouto Sorry for my ignorance. What is KEXT?
Google is your friend. 
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si_edgey On the contrary, this is actually great news because now we know who developed the KEXT. I have tracked him down and am making contact to propose the development of a KEXT for us. I will post updates here as we go on.
Another one of the articles on that site is interesting, albeit from 2012..
Flailing around the web revealed someone at Disney who has produced tweaks to X's configuration file for use under Linux; unfortunately this doesn't work in OS-X as the dithering is done by the driver.
It's probably way out of date but is very interesting to know how even people in the creative industry for huge corporations have needs to disable dithering.
Well, as said above, the kext might not do its work, although it loads.
After three full days of testing, I can say that I got as tired as before. The same feeling of overworked eyes and head/eye strain/pressure. And I'm pretty sure it's the iMac screen, because I managed to relax somewhat by playing on the iPad
This only shows itself after prolonged periods of intensive work, so I can spend 1-2 hours at the screen quite easily.
In the process, I also switched off Gamma Control for a while and returned from HD-709 color profile to the standard iMac profile, and after a short time my eyes started burning. This makes me believe that apart from macOS dithering, the iMac screen has brightness issues.