There’s a pack of textures you can download at BlendSwap for ArcViz and it includes what I consider to be an amazing light solution. It’s Emission with Blackbody as the color with 6000K
It’s phenomenal but I’ve never seen anyone do or talk about this setup before. Is this just some personal method someone set up or is there a logic to this that’s not popularized yet?
Not sure what you mean by this? This is pretty much the entire reason the blackbody node even exists. Incandescent lights are blackbody emitters, and many non-incandescent light sources are still described by their approximate color temperature. So it’s a handy way to approximate the color of different real world light sources, especially ones you have a spec sheet for.
On a side note, correctly representing spectral effects (especially for non-blackbody sources like fluorescent and LED lights) without spectral rendering is tricky due to something called metamerism https://en.wikipedia.org/wiki/Metamerism_(color) Basically, even if you take the RGB equivalent of a lamp’s spectrum and the RGB equivalent of a surface’s reflectivity, there’s no guarantee the resulting calculation will actually be the RGB equivalent of bouncing that spectrum off that surface. It will usually be very close, but if you’ve ever struggled to reproduce light tones like “ugly fluorescent green” this is part of the reason why.
Gotcha. I appreciate that deep answer - I’d seen the Node but mostly ignored it. Read up on your link; it’ll take a day or two to process but that’s a neat way of performing color solutions when it matters. I immediately think of using these values to affect sunrise and sunset light instead of just changing the RGB of a standard “light.” Really cool stuff.
If all light colors are driven by blackbody node like this:
Lamp Temperature.
Constant node group containing a global constant.
Add them together into blackbody temperature.
If you put positive or negative numbers to the constant node group, would that be equivalent to changing film white balance? Like, indoor incandescent lights change from red/yellow to indoor matched film white, which in turn turns outdoor light more towards the blue. Never did do this experiment.
To change the “film” light balance you should change either color management settings (RRT or curves) or do white balancing in compositor. By default Blender assumes sRGB white point which is D65 standard illuminator at 6500K. This color temperature is shown as white with sRGB display transform and default settings.
But yes, you could also “bend” the default white point by changing the lights instead by adding or subtracting a constant value from temperature of all lights to simulate the effect of incandescent or daylight balanced film.
