after having returned (a few months ago) a MBP 2020 because of eye strain I have now two MBP 13": a late 2009 running Yosemite and a mid 2012 running Catalina.
They are both non-retina, I guess the display technology is similar but they don't share exactly the same display, in fact the 2012 is brighter; here you can find all the details:
1) https://www.notebookcheck.net/Review-Apple-MacBook-Pro-13-Mid-2009-2-53-GHz.18780.0.html#toc-display (it says mid 2009 but I guess it should be "late 2009")
The graphic card, however, is different:
2009: NVIDIA GeForce 9400M 256MB
2012: Intel HD Graphics 4000
The MBP 2009 is way more comfortable than the MBP 2012 and when I use the MBP 2012 sometimes I have the feeling I had in the CRT era when I used a display whose refresh rate was < 85Hz: my eyes get tired.
Apart from the symptoms, what I see if I put the two laptops side by side is:
- the contrast seems higher in the MBP 2009
- on the MBP 2009 everything is more grayish, which maybe is not a good point in general but colors are more gentle on my eyes.
I have tried to install Yosemite in a partition of the MBP 2012, to compare the two laptops with exactly the same OS and settings but I can still see the difference. I've tried gamma control and I've calibrated the monitor but I can't get the same result I get on the MBP 2009, side by side they are still different.
Do you have any additional hints for me or can you give me additional explanations about why I am having problems with one of them? Of course I would like to use the MBP 2012 with Catalina (better performance, better security).
I have also tried to install in a partition of the MBP 2012 the OS the laptop was shipped with (Mountain Lion) and ... WOW I was not used to that look anymore: the icons look ugly but the interface is way more comfortable for the eyes you can immediately notice that! I don't think I am saying anything new here, but once again, that's the proof that (at least from my point of view) MacOS, talking about led strain & c., is getting worst and worst.