Rec709 Gamma settings for calibration in lighting env

I think I know the answer to this but just want to get feedback on how others are setting their Rec709 gamma when calibrating their monitors in different lighting conditions.

In my studio, my editing/grading room has a 6500K at < 10 lux, more about 3 lux. So using DisplayCal, the Gamma I set for when calibrating my display for Rec709 colorspace is Gamma 2.4. Then I have another room that has more of daylight coming in and measures between 40-60 lux. For the monitor in this room, I calibrate it for Rec709 Gamma 2.2. Both monitors are the same brand and model.

The Resolve project is shared between this two environments. Is it practical enough that the colors and brightness will be almost identical? Have you encountered this kind of lightning in your studio and how do you calibrate your display? Love to know so please share.

I still think 2.4 is only appropriate for a minority of viewing conditions. The majority of viewers are on smartphones, tablets, laptops, desktop monitors, and TVs in a well-lit room. I bet you Game of Thrones S8 Ep3 (Battle of Winterfell) fell for this. I watched that episode in 2 different environments. It looked adequate in my 2.4 TV that was in a mostly dark room. It was horrible on my 2.2-calibrated computer monitor in a lit room.

All of our grading monitors are calibrated to 2.4 in rooms equipped to be dark. In other situations, I typically recommend 2.2, but it is up to the colorist.

Regarding your question... it is a judgment call. But it seems you have it right.

Dom, thanks for your input. Much of what I do are for festival delivery and certainly they end up showing in someone’s living room so a 2.2 is the right gamma. However, distributors would ask for 2.4 and certainly for 2.6. We have a grading room that’s pretty much 0-1 lux for P3 and DCP delivery. Yes, it is a judgement call but as a very small house, we can only do so much with calibration and then testing to watch them in different environments and calibrated monitors. We also have only 3 rooms, so I have set them up so that each has the grading environment for 2.4 (broadcast), 2.6 (cinema), and the rest for 2.2 (web, home TV).

Don't overthink it. You could grade for 2.4 and export a version with 2.2 for TV/internet. Everybody will be seeing something different anyway.
Of course, I'd take all the effort needed for cinema in DCI P3, that's where it's worth it.