Blackmagic Forum

Can anyone from BMD explain the logic behind this simple fact that in ACES project if:
1) I add OCIOColorspace LUT to viewer and set input to srgb_texture (which does not include RRT but only gamut and gamma transforms) and output to out_srgb I get the same image as when...
2) I disable viewer LUT, treat MediaIn as ACES2065-1 (linear AP0) and convert to sRGB output using OCIOColorspace node (except in this case I don't get highlight clipping)?

Why does viewer apply an implicit conversion to srgb_texture? There are no other LUTs in viewer lut stack and OCIO conf is the same as I use in OCIOColorspace node. MediaIn has both source colorspace (should be named gamut instead) and gamma set to auto. It makes no sense whatsoever, whichever way I look at it.

It seems a problem related to the Managed LUT which defaults to sRGB output in ACES projects and manifests itself even when it is deleted. Whats more, changing the ODT in project settings clears all other LUTs in Fusion page and replaces them with Managed LUT, which ofcourse is plenty wrong in ACES project because Managed doesn't know anything about OCIO conf.

The whole LUT stack seems to be completely broken. Random deleted luts appear suddenly, stack might be clear and luts not enabled, it applies some lut anyway, right click in viewer resets enabled state and so on. Sometimes I can't delete existing lut, sometimes there are no luts in stack but are applied anyway and appear under delete command...

Anyone else seeing this funky behavior with viewer luts? Is this a "feature"? Or is no-one in their right mind trying aces through fusion page?

Hello
I've recently tried Fusion with ACES color management. What I discover/Understand :

The LUT viewer setting are good

The Output Space is the same as the Project's ODT
BUT the calculation/result is wrong.

So instead of that I turned off the LUT viewer and add an "ACES transform" tool

I set the Input transform to ACEScg witch is the Fusion Page's Colorspace and I set the OutPut transform the same as the Project's ODT.

For me ACES Transform + LUT viewer switch off give the same result as the EDIT/COLOR viewer (with grading bypassed of course)

Don't hesitated to correct me if I'm wrong

ACES transform works, sure. But having explicit transforms to work around software color management bugs kind of defeats the whole purpose of color management.

Hendrik Proosa wrote:ACES transform works, sure. But having explicit transforms to work around software color management bugs kind of defeats the whole purpose of color management.

I totally agree

Has anyone found a way around this issue? Super frustrating!