I've been reading a bit on realistic lighting in Blender and was introduced to realistic physical light values, as well as color management through Filmic Blender and the Exposure slider.
This excellent tutorial suggests that the value for direct sun lighting outdoors is a whopping 441 units. This completely blows up the lighting in the scene, making it look bathed in nuclear fire.
A swipe of the Exposure slider in color management fixes that. However, if I'm not mistaken, this also messes with other light-related things which are organized around more "relaxed" numbers, including...
The Emission shader.
I have a character with glowing eyes. In my "regular", unrealistic, "if it looks good it works" lighting setup, I used a Strength of about 4 to control the emission on her eye textures (combined with the Diffuse via an Add shader), which made them look sufficiently glowy. However, with sun lighting cranked all the way UP and exposure all the way DOWN, it feels like they barely glow anymore.
Blender docs say the following about Emission shader strength:
Strength of the emitted light. For point and area lamps, the unit is Watts. For materials, a value of 1.0 will ensure that the object in the image has the exact same color as the Color input, i.e. make it ‘shadeless’.
This confuses me. Does this mean that Emission material strength doesn't change regardless of the lighting? How can you even go beyond "shadeless"? Does this mean Emission materials don't use Watts as a unit, and so I can't apply the realistic lighting technique?
- Do materials need to be changed according to the scene (lighting, exposure), or is the simulation realistic and materials only need to be configured for their realistic physical properties?
- Is it normal that realistic light values completely destroy the scene when using default Exposure, and it needs to be dialed way down?
- Is there a way to calculate realistic, physically correct emission for materials? (Ex. the emission of an LED lamp on a monitor)