Hemispherical ambient light calculator?

[wickfut]

Are there any sites which calculate the correct colour tones to get realistic ambient light colours for the scene?

Could it be done automatically by taking an average of for eg. the sky/sun colours vs the ground reflection colour?

Is there a way to do it correctly for different weather types. I understand it's usually some sort of orange-red/blue-cyan mix, I just don't get how to work it out for different areas/weathers/lighting?

for eg. what are the usual colours for darker dungeons? red/green?

How do you do it? At the moment I tend to do blue and orange and adjust the brightness amount so the skin tones and shadows match what I see as correct and so there's no radioactive skin effect, obviously this won't work once you add in the direct light colours etc.

any tips?

[ENBSeries]

Ambient is a fake representation of diffure light reflected from environment and usually it means from the sky. Directional ambient is just bit improvement to make separation by vertical axis, but it is not much better by precision than single ambient, so calculations are barely correct, dont expect much. Okay, so the blue color of the top means that you get sky hemisphere with clouds and blur it to get average color for ambient, but exclude sun as it's applied as directional light. This method is similar to IBL, just have lower precision. Bottom ambient is really difficult thing, because it depends from surfaces which reflected light, so for a grass reflection is a multiplication of green, yellow and blue colors (sun and sky both reflected from grass, but of course sun is more intense, so blue value is high only at the evening/morning or when sun covered by clouds but sky is not), snowy areas gives whiter reflection, dark areas gives less than brighter, so on. You can't even blur scene bottom hemisphere to get that ambient, so without extra lighting effect (one day i should do it) it's not possible to make good looking bottom ambient for all places.With interiors it's simpler, all ambient types are just indirect lighting and you can set it to how much directional and point lights lit some area and the reflection from it is ambient, but again, this light have heavy locality and there is no generic single value. You can't just set black ambient too, cause lot of indirect diffuse reflections occurs. So it's purely up to you how to find balance of not making too high values which produce too much bright objects in dark areas and not make weird darkness on the back sides where location is lit enough. Again, this need extra effect to fix issue partially.

[wickfut]

Thanks, thought as much. I shall keep fiddling

Specific to the dogma enb settings, are there any linked values which aren't easily figured out, for eg your skylighting settings linked to ambient, and your ambient desaturation being linked to direct light amounts etc.

Are any lighting settings linked to actual sky/sun colours or is that purely direct light colours?

[ENBSeries]

This depends from what you call linked. No things like automatic ambient computation when some color values used to create others. Skyrlighting just multiplier for ambient and sun, so in some way they are linked, but not generated like in main question of yours about ambient calculation.