Monitoring Scene Linear w/ sRGB primaries

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I cannot seem to find the correct lut/viewing rule for viewing Scene Linear w/ sRGB primaries. I can get pretty close with many things (rec709 OOTF is the closest, and it’s very similar to using the old PhotoMap)

I can go from any camera to ACES, to ACEScg, to any other camera and have a correct viewing rule, but I cannot find one for sRGB primaries. Should I build it? I feel like it really should be there given “Scene Linear rec709/sRGB” is one of the four linear options, there should be a way to view it correctly, no?

to clarify, what I’m seeing is a mild increase in saturation. Gamma seems fine, but in theory the primaries should stay visually the same, relative to the switching view transform, yet none of the view transforms accomplish this.

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Hmmmm…ill have a look. not my specialty, but hey, thats never stopped me before.

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Yeah, I can’t figure it out either. We’re going to need to invite some smart people.

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per the true expert @doug-walker :

No, viewing sRGB primaries through the ACES view transform will not look desaturated, it should look exactly the same regardless of what primaries are being used.

That’s what I meant about “a conversion is inserted”. The way it works is that the view transform is tagged as expecting a certain color space on input and the media is tagged as being in a certain color space. So based on that information, Flame inserts a conversion transform to make the view transform compatible with the media being viewed.

The conversion happens whenever the viewing rule uses one of the “Any …” options in the Allowed Color Spaces column. If Allowed Color Spaces is just a single color space (for example, whatever the viewing LUT expects), then no conversion is inserted and that view transform would only show up as an option when viewing that color space.

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So basically, if you are using, for example, “ACES to SDR Video” it will say “Oh, shit, I see you are feeding me a Scene Linear / sRGB image. no sweat. I’ve got you bro, I’ll convert the primaries to where they need to be.”

So the answer is “if your footage is tagged correctly, you can use any of the linear view transforms.” I’m definitely gonna need to spend time with this to let it seep in correctly. I feel like one of the apes in 2001 at the moment. Haha.

Another argument for tagging footage correctly.

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Totally. Every time I have to open up a r3d file it’s as though there is no truth anymore.

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