How does colour grading work?

Cinema cameras record log: a flat, grey file that keeps about 7.8 stops above a grey card, where a Rec.709 video file clips just 2.5 stops up. A 3D LUT, a cube of input and output colours, turns log into a normal picture.

Read how it works: How does colour grading work? · The history of colour grading · More boxes on Glassbox

Chapters in this interactive model

1. Flat log footage and the LUT: Why cinema cameras record a grey, washed-out picture, and how a LUT brings it to life.
2. Lift, gamma, gain and the scopes: Three wheels for the shadows, the middle and the highlights, checked on real scopes.
3. Making two shots match: Two cameras, two times of day, one scene that has to look continuous.
4. Qualifiers, power windows and skin: Change only the sky, only a shirt, only one face, and keep skin looking like skin.
5. Teal and orange, noir and the creative LUT: Once the shot is balanced, the colourist gives the film its mood.
6. The grading suite, HDR and colour gamuts: Why a colourist grades in a dim grey room, and why every film is graded more than once.