How to match exposure and white balance across shots by measuring skin tone
Ask Vizard Agent to measure the skin tone and the black level of every shot before grading anything. Those two numbers are what "matching" actually means. They let white balance be fitted per camera and exposure per shot, two different problems that a single eyeball adjustment tries to solve at once.
What do you type into Vizard Agent?
Name the two measurements to Vizard Agent. Asking simply for the shots to be matched invites one overall grade across everything; asking for the skin tone and the black levels to be measured turns the same job into a fit against numbers. Saying the warmth stays protects the thing a fit will flatten.
Prompt
What does Vizard Agent actually do?
Grading by eye fails in a specific way: your eye adapts to whichever shot is on screen, so each one looks correct while you work on it. A camera has one white balance for the whole shoot, while exposure changes shot to shot as the light does, so the two are fitted separately. In the session behind this article it:
- Measured the exposure and colour of every shot in a multi-shot film from two cameras, then the skin tone and the black level shot by shot.
- Fitted a matching grade for each shot against the reference, with white balance fitted per camera and exposure per shot on top of that.
- Rendered the graded shots and judged the match on real frames. The first fit had corrected everything, including the natural warmth that was supposed to stay.
- Refitted exposure only, leaving the colour where it was, then fitted one exposure per take at a brighter target.
- Rendered the corrected grade and rebuilt the film.
When does this not work well?
Measurement needs something to measure. A shot with nobody in it has no skin tone, a shot lit by a coloured source is meant to be that colour, and clipped footage has no detail to recover. Log and standard footage need converting first, and heavy compression makes the measurements noisy.
Common questions
Why skin tone? Because viewers know what it should look like. Vizard Agent anchors the fit on it.
Will it flatten my look? Only if you let it. Say the warmth stays and Vizard Agent refits exposure alone.
Can I pick the reference shot? Yes, and you should. Otherwise Vizard Agent fits towards an average.