I always have my flares output separately then treated and comped in a comp node. One of the reasons why is that Action only displays flares and other optical effects as Additive.
Is there a way to force Action to use screen mode for opticals? It’s hard to work with and preview when the opticals go nuclear.
Curious if @fredwarren has any insight on this?
Are you adding them in rec or ACEScg?
Rec
This isn’t a problem with action or actions lens flares. This is because you’re choosing to use math in rec 709 and rec 709 doesn’t support real math. In other words, one plus one does not equal two in Rec.
Do an input transform from Rec to ACEScg, do your lens flares, invert afterwards, and Bob’s your uncle.
Yeah I know. But considering that a lot of us do work in rec, and this has been an issue from before Aces was a thing, it is odd to have to do that workaround.
There should at least be an option to render properly without switching color spaces back and forth.
Come on GP, embrace ACES 
Meh.
Dude. For reals. It’s not that hard. Seriously. you can still get all your renders in Rec. You still deliver in Rec. But in your Batches you add 2 nodes and it’s a major upgrade. It would almost make it look like you knew what you were doing.
okay fine, don’t learn ACES. But every time you ping Fred when it’s a question that is answered by ACES, I’m going to text you this link.
I thought going Rec to Aces and back to Rec was supposed to be a no-go with anything of quality. I mean, I’ve done it, but it’s just for commercials and mostly to get a nice linear blur.
It is almost never a problem and not worth dealing with.
Do source nodes still work?
It’s been an eon since I tried, but it used to be possible to encapsulate everything from an action into one layer and then use the compositing characteristics of that layer as a ‘blend mode’.
Also, if anyone wants conveniently concatenated color transforms and related color policies I’m happy to share the flame_colortoolkit.
Not an issue. Going from ACES to Rec and then back to ACES is a no go because of the gamut range difference. I flip in and out of aces all the time, even on pre-graded Rec709 stuff. It’s like how you can convert 16bit to 10bit, fine, but not 10bit to 16bit.
That is not the case at all. Using Input Transforms to move in and out of ACEScg, to and from Rec 709, to perform certain operations in the appropriate math word is totally fine.
But if I wanted to be pedantic, I might say it’s technically a problem on every blur (motion blur or DoF) and add operation you perform. Just sayin… linear is the world to comp in. You’ll like it! 9/10 dentists recommend!!
Thanks Randy
How about an example of the CM node and rule. Not being a dik. I really want to know.