Saturation

Move every pixel towards or away from its own grey.

A pixel's grey is its Rec. 709 luma, and factor is how far the pixel sits from it: 0f lands on the grey and turns the frame monochrome, 1f leaves it alone, and 2f pushes each channel twice as far from the grey as it started. The luma itself is unchanged at any factor, so a grey pixel stays exactly where it was.

Throws