How to get black mist / night fog?

Hi there, I am trying to replace the processing-heavy volume fog in my scene with a mist. I have been able to add a mist effect using the advice as given here:

https://blender.stackexchange.com/questions/94520/how-to-create-mist-in-blender

However, the mist is always grey, and although it can be coloured, adding an invert node (when it’s grey) does not change the mist color from grey to black. I’ve tried multiple options on the color mixer, but nothing seems to produce black mist (i.e. objects fade to black at further distances). Does anyone know if this can be done?

I’m also having a few problems with the depth, it seems some how pre-set to be only over a small range going from no mist to full mist. I have noted their is a “mist pass” section under the world settings tab, but changing the depth options in there have no effect.

My current node setup in compositing looks like this: https://imgur.com/a/pMXeJb2

According to the post you linked, you need to pipe the mist into a RGB or color ramp node and then manipulate the color that way. (As a note the inverse of grey is grey).

I tried that but the problem is, if I use white or any other colour on the ramp, it looks like this:

But if I make the color at 1.0 (which is the spot from which it takes the colour, it just gives:

E.g if the fog colour is black, it does nothing. The node setup for the images above was like this:

(i unhooked the viewer so the node background wasnt messy)

I also tried “inverting” the image before the mix node to make the black areas (closer) from the mist pass white and the “misty” bits black to then mix it with add, or subtract or something, but that wont work either because the far away background from the mist pass then becomes transparent.

https://imgur.com/omfa5Ks

I’m not sure the mist pass is built to work this way. As one looks at things further in the distance, the mist/haze makes them appear desaturated and lighter. I think putting something dark in the mist and trying to put it in the distance like a black fog or something, just flips the effect around. I haven’t found a way to push this in the correct direction and with the effect you’re looking for.

How about negative lights? Think that might help? Maybe a mesh light in the background that’s negative, sucking light away from the scene?

Or maybe better, set the World to have a volumetric absorption shader on it, and slightly dial down the color from white. Watch the distances in the scene darken.