White balance in nuke

nuke_whitebalance

In this post I am going to share a quick tip on how to white balance your images inside nuke without “burning” your image with the withepoint default control. The basic idea is to average out the values from the whitepoint.

“Raw” Image

raw image nuke

I am using the image above for our example. It’s an HDR image with values higher than 1.

Default Grade

default grade nuke

Start by creating a grade node and pick a reference point for the whitepoint. As you see this will wildly change your image luminance. So we need to find a way to keep the values under control.

Create whitebalance control

create white balance nuke

Right click in your node proprieties bin and select manage user knobs… in the Add dropdown select RGB Color Knob, name it “whiteBalance”, click ok and then done to close the creation window.

In your node “user” tab you should have a color picker, use it to pick a color area of your image where you think it should be white. Your viewer should be connected to the original image so you dont pick the bright colors of the grade node.

White balance expression

nuke edit expression whitepoint

In the grade node whitepoint attribute, right click in the animation menu and select Edit expressions.

nuke whiteBalance expression

Now enter the following expressions in the r,g and b inputs:

whiteBalance.r/((whiteBalance.r+whiteBalance.g+whiteBalance.b)/3)
whiteBalance.g/((whiteBalance.r+whiteBalance.g+whiteBalance.b)/3)
whiteBalance.b/((whiteBalance.r+whiteBalance.g+whiteBalance.b)/3)

This simple code will always avarage your values to 1 and keep your image luminance.

Final Result

white balance nuke final

As you can see we no longer have the luminance issue, try to pick a different area of the image to set the white balance.

  • Jose Diaz

    Great tip! Thanks a lot.