Mid gray luminance slider inside resolve

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Hi! I’m looking for some sort of technical explanation of the “mid gray luminance” slider in resolve. It’s measured in nits and defaults to 15. It’s specific to hdr odt’s and aces color management. Any info would be super helpful!

Thanks

It determines where mid-gray (ACES=0.18) maps to in luminance (encoded w/ PQ). The tonescales in the ACES 1.2 HDR Output Transforms are defined based on three key points: “black”, “mid-gray”, and “peak white” (the curve draws itself based on this input). However, if you change mid-gray, the curve itself doesn’t change, it just makes your image brighter or darker overall (shifts the curve left or right on the log-exposure axis of an exposure vs luminance plot of a tonescale). It is equivalent to an exposure adjustment. In general, you shouldn’t be using it. It’s there for technical reasons in Output Transform creation but really shouldn’t be accessed unless you know what you’re doing.

Bottom line is that I recommend you leave it at its default value and make any exposure adjustments as a part of your creative grade.

Got it, good to know… thanks for the insight!