Gamma calculator help
I have recently recalibrated my JVC projector since the bulb has aged. I typically calibrate to 2.4 but wanted to calibrate to BT. 1886 this time. I use HCFR for my calibration software. The issue is, I don't know how to calculate the correct luminance for each of the display patches (e.g., 10%, 20%, ... etc.). I have always used an Excel sheet that has floated around here that I can define a gamma log function (like 2.4), give it my maximum light output, and it tells me what each luminance is supposed to be. That is, if my 100% max luminance is 16 cd/m^2, then my 50% should be 3.03 cd/m^2, 90% should be 12.43 cd/m^2, etc.
I cant seem to find a similar calculator for dialing in my BT. 1886. Obviously it will have to be more complex than the typical gamma calculation since it takes into account non-zero black level. Can anyone direct me in the right direction as to how to calculate each luminance range so I can dial in my gamma with HCFR and my JVC? The JVC has a 12 point gamma correction. Perhaps there is an updated and even more automated way to calibrate my gamma to BT. 1886 with HCFR that doesn't require this kind of manual calculation?
Thanks for the direction.