How to normalize WB as the sun goes down on my interview

My solution to this was to place each clip (of 15 to 35 mins duration, shot during an evening outdoors) onto the sequence, add the levels effect, go to the first frame, experiment with the various options to make the first frame look right (using the WFM and eyes), once happy add a keyframe to all the controls that I have used, go to the end of the clip, add the same keyframes and adjust those controls to give the same look as the first frame. It tracked pretty well throughout each take.

There were 10 of these clips on each camera, four cameras in total. Started at 18:30 finished 23:00 by which time the last scene was lit with lights.

I had to do it this way, as there was not time to do a re-white balance on the cameras for each shot. So, one WB at the start and iris setting was also done only once. (Except for the final lit scene.)

Oh joy oh rapture all foreseen ... to paraphrase a Gilbert & Sullivan song. (Been there, done this ... sigh)

Might be faster to re-shoot, depending on your need for accuracy in tonal changes (or lack thereof) and capabilities with grading.

You've got probably a number of different major things going on, and all will affect the final look, past the general color-balance part. It is probably wiser at this point to make it look like "this was intentional", and show some of the difference as part of the natural time the interview was shot, as then some of these things can just be allowed to change at least mostly without tight control.

I don't know what 'practical' lights were going at the time of the interview, room lights or such. Or whether you had some additional controlled lighting going. That of course can help, or be an issue.

As that light source was fading, the range of hues, their balance, was of course shifting, and it's not nearly as "clean" as sliding a temp/tint slider around. Undoubtedly both types of contrast changed ... Luma and Saturation ... both for the total range and also for the shading/feel within shadows, mids, and highlights. They've probably shifted between the beginning, middle, and end of that interview. For example, the shadows hues/tint may have been more controlled by scattered sunlight early on, and more by light coming from other sources later in the interview. Changing more in some parts than others.

This is all assuming using Lumetri color workspace. The simplest way is to set a grade at the beginning, then make a keyframe where it starts to change, and perhaps go all the way to the end to make another grade, but first bring up the Reference monitor with the first frame showing so you see for comparison between the first frame in the Reference monitor and the last frame in the Program monitor. Try and balance both luma (light/dark) and saturation total contrast levels first, then try and adjust the color balance. You may need to use either Curves or particularly the Color Wheels to move shadows, mids, and highlights differently.

Especially note the Vectorscope YUV and I'd go with RGB Parade on the Lumetri scopes while doing this. The scopes will give you a better idea of where things have changed than your eyes will.

You will probably then need to add keyframes in several places, and for each one, adjust the color & luma contrasts again to match the image of the first frame in the Reference monitor.

If you post a screen-grab or two, we can probably give some particular advice.

Neil