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Editing and finishing3 min read

LESSON 120

Colour correction versus grading

First make it right, then make it yours.

IN THIS LESSON

  1. Two jobs, often one word
  2. Where grading came from
  3. Correction first
  4. Then the grade
  5. Practice: an order of work

Two jobs, often one word

Colour grading changes the look of an image in post-production, adjusting contrast, colour, saturation, detail, black level and white balance, for film, video or stills. The words grading and correction are often used for the same process. In working practice many editors and colourists separate them: correction makes shots technically right and consistent with each other, and grading then gives the film its intended mood. That distinction is a common working habit rather than a formal definition, but it is a useful order of work.

Where grading came from

Before digital tools, colour was adjusted in the film lab during printing, a process called colour timing. The lab varied the strength and colour of the printing light, measured in printer points, with seven to twelve points making one stop. Because the result could not be seen straight away, labs used a Hazeltine analyser to preview the changes. A timer watched the film with the director and cinematographer, took notes and set the points scene by scene on a paper tape that drove the printer. Digital grading in Hollywood films became common in the 2000s.

Correction first

Correction sets each shot's exposure and white balance so neutrals look neutral and faces look natural. Colour balance tools adjust red, green and blue so that grey and white objects are rendered correctly, which is why the method is also called grey balance or white balance. The second part of correction is matching: shots in a scene must look as if they were filmed at the same moment, even if the light changed between takes. Scopes such as the waveform and vectorscope help here more than the eye does.

Then the grade

Grading is creative. It can warm a memory, cool a threat, lift a hopeful scene or crush the shadows of a frightening one. It usually happens in a darkened, controlled room called a colour suite, on a calibrated monitor. Modern grades often combine many layers and masks, so a face can be lifted while the sky is darkened, as photographers do with dodging and burning. A colourist also prepares versions for different screens, because the same grade can look different on a cinema projector, a television and a phone, and each delivery may need its own small adjustments.

Practice: an order of work

This is working practice. Convert log footage to your working space first. Correct exposure and white balance shot by shot. Match the shots within each scene. Only then apply the look, ideally on a separate node or layer so you can switch it off. Watch the whole film at the end, because a grade that looks fine in one shot can feel tiring over twenty minutes. Take breaks, because eyes adapt to a colour cast within minutes and stop seeing it. Compare against a neutral reference image now and then, and if possible look at the grade again the next morning before you sign it off.

Try it today

  1. 01Pick three shots from one scene with slightly different colour.
  2. 02Correct each so a grey or white object is neutral.
  3. 03Match the three to each other using the waveform.
  4. 04Add one creative look on a separate layer.
  5. 05Toggle the look off and on and judge what it adds.