Do we need to change ACEScct

[SeanCooper]

First just a small technical correction, LogC4 exceeds ACEScct at EI 1600 and above (inclusive).

While the conversation has focused on the ALEXA 35, it need not be, this ACEScct update (or lack thereof) will last for a long time so should be viewed on the ~10 year timescale if I base it on the current lifespan of ACEScct. I just view it as an opportunity for change and to anticipate needs over the next decade or so ( not that this is the last opportunity, but certainly a natural break ).

I definitely agree the principle problem area is on-set: with quantization, CDL behavior, exposure evaluation, and exposure latitude working against each other.

Enabling/promoting native camera working spaces in the ACES ecosystem is one approach, via AMF/CLF or otherwise.

@sdyer

ACEScct can be defined as “ACESlog with AP1 primaries”. The shorthand name could be recommended to change to simply ACESlog (implying AP1) or remain ACEScct (implying ACESlog/AP1), but the important thing is to assign a name to the log encoding itself, separate from the color primary encoding.

I would personally be against this if nothing changes. It will end up being a lot of needless work and headache for those in the color trenches just for typographic aesthetics. If you need an independent unique name for the encoding curve, you could just introduce “ACEScct Curve” or “ACEScct Transfer Function”