Movie Render Queue + Post Process Material = very different results than Viewport! Is this a bug?

[Crakmaks (lumines_labs)]

Hey everyone,
I’m hitting my head against a wall here for several days now.

When utilising a Post Process Material on a CineCamera with any kind of brightness change, I’m getting exponentially stronger results in the Movie Render Queue in comparison to the Viewport.

With the default settings the MRQ is supposed to give the exact same results as the viewport, correct? Because it does without the Post Process Material or one with a node that doesn’t change anything. But as soon as I modify values, for example an Add Node with 0.25, the render results start to drastically differ.
Is this behaviour a bug or some colorspace shenanigans?
Because by default the reults do look the same.

To illustrate the problem I created an empty scene and showcased the differences with brighter and darker settings.

In all the examples the Viewport is set Game Settings for the exposure and the cameras exposure is set to manual.

If it’s not a bug please tell me how I can get consistantly the same results between viewport and MRQ.

[EliasWick]

You can change the material “loading” order of the post process effect. You might want to have it run before the post process effects. It’s done per material in the long list of settings like Material Domain.

[comlys (Shaun Comly)]

I believe the viewport is srgb in and MRQ is linear in. So it is not surprising that they don’t match.

[EliasWick]

That is a good point indeed. What is the best approach to resolve this, so that what you see is what you get?

[comlys (Shaun Comly)]

You would have to switch the blend location to before the tone curve is applied.