Lift, Gamma, Gain is a set of color wheels designed for primary color correction. Unlike secondary color correction, which involves working with isolated colors, primary color correction helps you change the entire color tone composition of the video. This means fine-tuning dark tones (Lift), midtones (Gamma), bright tones (Gain), or the entire image altogether (Offset).
The tricky part is that by using either of these controls, you aren’t only correcting shadows, highlights, or midtones: the changes made with the Lift, Gamma, and Gain wheels affect the entire spectrum of tones. Feel free to watch this video explanation before continuing.