Johnson Martin writes:
In order to better understand the lighting system in the Cycles render engine, I've decided to dive into understanding how Cycles uses physically based units to accurately measure the intensity of emissive materials. On the surface, the values used by Cycles seem somewhat arbitrary. But digging deeper I've found that once again, Cycles has a facet of accuracy quite underestimated by the common user.
So let's dig in.
8 Comments
Thank you for the article. It's always nice to get a better understanding of the basis for the wide range of value settings in blender.
Definitely. That's what drove me to write about this topic. :)
Thanks mate
Thanks man, very interesting tutorial
Nicely done putting this complex topic into plain language
Kelvin values are not the good thing to use.
Why?
Because for example the moon has a red color in kelvin. But we don’t see the moon red right?
Kelvins values are not the human eye perceived colors, so it’s useless.
Maybe someday we’ll have a node containing color charts under various circumstances.
https://310blender.wordpress.com/2016/01/25/practical-workflow-for-realistic-renders/
Didn't notice your comment. Sorry!
I'm not sure if that is 100% true. Sure, our eyes don't always view colors as they are, but this does not negate that color should be reproduced correctly.
Also, the moon has no direct kelvin value since it is not an emitter. Realistically, it would be the Kelvin value of sunlight, around 4000-5500k (the moon is also dielectric , so the reflection of light is more or less pure). Often times it seems as though the Moon is white or even blue in photos, however, this is generally due to improper white balance.
Thanks.
Personaly I tried kelvin values and didn't worked for me at all.
Instead I use the chart created by Jeremy Birn in the article on my blog. I took every color and converted to an RGB value, then made a group node with all the values and when it's applied to light sources in my scenes (without textures and only white/gray materials) the light color feels right immediatly.
Cheers.
Ed