Rich's Tongfamily (Richtong.net add-on)

I’ve been using the Datacolor Spyder3Studio for years now to get a good calibration on monitors. Despite the fact they are up to Spyder5, this has really served me well even with out of data software.
However in trying to calibrate a Monoprice UHDTV display, a 28 inch TN monitor, I had my first trouble. Running on Sierra MacOS, the color kept getting redder and redder. Also, the readings were inconsistent. I would get the display to show 200 cd/m^2 and then during calibration it would turn redder and redder.
I finally had to delete the Spyder calibration and start all over, this seemed to help. FWIW, the sRGB out of the box calibration is actually very close to the 6500K, 2.2 Gamma that I normally use, so if you do not want to calibrate this, just set it to sRGB color space and take the brightness defaults gets you to 200 cd/m^2. That’s pretty bright, but works in high ambient light rooms. If you want a good display for color print photography, they you want it much darker and more like 120 cd/m^2.