What is Pivot in Color Grading?

Question

Most of the controls I at least have a basic understanding of from Photography and other design applications (Affinity Photo / Photoshop / Lightroom etc). But not Pivot.

In the SpeedGrade Manual the word Pivot doesn't exist at all. Pretty big omission but I'm resourceful and know other applications exist. So even though I don't use it I pulled up DaVinci Resolve's guide which states

Pivot: Changes the center of tonality about which dark and bright parts of the image are stretched or narrowed during a contrast adjustment. Darker images may require a lower Pivot value to avoid crushing the shadows too much when stretching image contrast, while lighter images may benefit from a higher Pivot value to increase shadow density adequately.

Perfect cause this actually sounds like exactly what I need. Except when I use it there's absolutely no change in my video and I've got no idea why:

Here's the original:

Here's the footage with the pivot greatly pushed up, yet no change:

I don't know if I'm not understanding the Pivot or what. I'm not seeing any difference though.

Answer 1

As you know, the contrast function darkens dark colors further and lightens light colors further. Software without a pivot parameter assume that the point where darkening becomes lightening is exactly in the middle, at 0.5 (for a color range of 0 to 1). Those with a pivot parameter allow to move the pivot point up or down. Shifting the pivot slightly down (e.g. from 0.5 to 0.4) results in dark-medium colors (let's say 0.45) not anymore being darkened, but lightened.

In your image, the effect is not that visible because most of the colors are already very bright, very dark, or just in the middle.

If you want to lift or lower your midtone details, I would suggest that you use a gamma or midtone control instead.