White balance node for compositor
I don't know why I couldn't find this suggestion here yet, and that gives me the impression I'm suggesting something really stupid because of something I'm not aware of.
The fact is that I miss the possibility to adjust the white balance in the compositor and I believe it could be useful to many artists as well. And now that light groups are implemented, this would be even more useful, I believe.
I saw many discussions over the internet about that and the lack of this kind of support in Blender, so I believe I'm not making any mistake by suggesting it.
If that is a stupid suggestion I'm sorry for that, and I would be delighted to know how to achieve that with the resources we have now.
7 Comments
Source: White balance / color matching between video/render for vfx shots - Blender Stack Exchange
I actually know how to use curves, what I meant was a way to accurately control the color temperature of light sources in the compositor as we normally need to set up everything from IES maps to blackbody values to get physically accurate light setups, and I think it does not make much sense to tweak that by eye in the compositor. Of course, that's what I do while there's no better option. I could also use the Photograph addon if I had it, but I believe it's quite a basic function that could help a lot if added to the vanilla Blender. Especially now that we got the wonderful light groups implemented.
Until then, I think the best option is to study a bit and try to create a node group myself.
I made it! It works wonderfully and covers color temperatures from 2000 k to 15000 K. Te node group is so simple that makes me laugh.
I just needed to bring a blackbody curve to the equation.
Hello! I searched for a solution for whitebalance in the compositor and found this, I wonder if you would be willing to share your solution for the nodegroup? I've tried to make my own but can't seem to make it do what I want.
I agree, but you can do white balance on the video editor, is one of the modifiers
That doesn't work as I wanted. actually, I wanted to work with the white balance adjusted as you do in a photo camera setting the color temperature of the lights you are working with. I came up with a set of node groups for this purpose and actually, that worked pretty well. I even have completely replaced the blackbody node from blender, which is based on a color sample chart, and created a node group that does exactly the same, but it's based on RGB curves instead.
Another node group in the compositor allows me to define which color temperature I'm working with and adjusts the image automatically. If I use a lamp of 2500 k I simply adjust the white point to 2500 k and the light turns white.
Also created another node group that works exclusively with light groups and allows me to adjust 10 light groups simultaneously (if the lights are white) and this node group applies the color temperature I specify, based on the blackbody curve, to the selected light groups.
It gave me a lot of work and study to find out how to build that and create scientifically accurate RGB curves, but I'm happy with the results, and I provided the blend file with the 3 node groups for anyone who wants it at Blender Artists forum.
Sadly I can't upload screenshots here to illustrate what I wanted.
But ok. The point is if I make a picture from a scene with a camera set for 6500k the appearance of the lights is different than if I set the camera to another white point. But what value should that be? Should that be set confiding in my personal taste? My eyes?
Anyway, that doesn't matter anymore because I already created an awesome node group that will not only allow me to adjust that particular case, but also have accurate values for color temperature changes using the light groups. Accurate, not set using my eye that can be tricked easily by the way our vision adapts to certain light conditions.
If I want a lamp of 3000k to look like one of 4562K I can. And I can be sure that the values are accurate and not just pretty.
That's what all this was about.
And for the record. Now the node group works for lights from 1000k to 40000K. Yes, I know it's more than we will ever use, but it does hurt to be able to do something even if you never need it, right?