What Is Color Grading?
Color grading is the post-production step that gives a video a deliberate, consistent look by adjusting its tone, saturation and color balance. It usually follows color correction, which makes the footage accurate first: neutral whites, correct exposure, shots that match. Correction makes the picture right; grading makes it feel a certain way.
Color Grading vs Color Correction
| Color correction | Color grading | |
|---|---|---|
| Goal | An accurate, neutral picture | A deliberate mood or style |
| Reference | Neutral white, natural skin, legal levels | The creative intent |
| Typical work | White balance, exposure, contrast, matching cameras | Teal and orange, warm nostalgia, cool tech, black and white |
| Order | First | Second |
The two usually happen in the same tools and often the same session, but the order matters. Grade a shot that is still too warm or slightly green and every later decision is judged through that cast; you end up fighting it with controls meant for the look. The craft is older than software: in the photochemical era a lab color timer set printer lights shot by shot, a job called color timing.
Primary and Secondary Grading
A primary grade changes the whole frame by pixel value: exposure, contrast, white balance, saturation, and the lift, gamma and gain controls that move the shadows, midtones and highlights. The ASC CDL (Color Decision List) writes a primary grade as ten numbers: slope, offset and power for each of red, green and blue, plus one saturation value, applied as out = (in × slope + offset)^power. Ten numbers travel easily between apps, which is how a look set on location reaches the edit.
A secondary grade changes only part of the picture. A qualifier, or HSL key, selects pixels by hue, saturation and brightness, such as only the skin or only the sky. A power window is a shape, often tracked to follow movement, that limits a correction to one area, such as brightening a face. Shot matching, making every camera angle look like the same scene, is per-shot work that often uses both.
The Controls and What They Move
- Exposure, lift, gamma, gain. Exposure moves the whole tone curve. Lift moves the black end, gain the white end, and gamma bends the middle without moving either end.
- Contrast. Steepens the curve around a pivot, usually middle grey, so it darkens shadows and brightens highlights at once. When footage looks flat, a gentle S-curve through the midtones usually reads better than a contrast boost.
- Saturation. Scales how far each color sits from grey. Rec. 709 weights brightness as
Y′ = 0.2126R + 0.7152G + 0.0722B, so a desaturated green turns light grey and a desaturated blue nearly black. - Temperature and tint. Temperature is the blue to amber axis (tungsten light is about 3200K, daylight about 5600K). Tint is the green to magenta axis; LED panels and fluorescent tubes often push green, which no temperature change fixes.
What a LUT Is, and What It Isn’t
A LUT (lookup table) is a precomputed map from input color to output color. A 1D LUT is three independent curves, one per channel. A 3D LUT is a lattice of output colors indexed by input RGB; common sizes are 17³ (4,913 points), 33³ (35,937) and 65³ (274,625), with the values between points interpolated. The usual file format is the plain-text .cube.
There are two kinds. A conversion (technical) LUT turns log footage into a viewable Rec. 709 image. A creative LUT is a look. Neither is a grade: a LUT is a fixed function that knows nothing about your shot, so two clips exposed a stop apart get exactly the same mapping. Correct exposure and balance first, convert log first, and put the creative LUT last.
Log Footage
Log profiles such as Sony S-Log3, Canon C-Log and Panasonic V-Log spend the camera’s code values on dynamic range rather than on a viewable contrast curve, preserving highlight and shadow detail a standard profile would clip. That is why log looks flat and grey straight out of the camera. It isn’t broken or underexposed; it needs a conversion to a display space such as Rec. 709, through a conversion LUT or a color-managed workflow, before or as the first step of grading.
Scopes
Scopes measure the picture so you aren’t relying on one screen and tired eyes:
- Waveform: brightness across the frame on a 0 to 100 IRE scale. In 8-bit Rec. 709, legal video runs from code 16 (black) to 235 (white); in 10-bit, from 64 to 940.
- RGB parade: the red, green and blue waveforms side by side, which makes a color cast obvious.
- Vectorscope: hue and saturation on a circle. Skin tones of every complexion fall near one line, the skin-tone line at about 123°.
- Histogram: how many pixels sit at each brightness level.
Eyes adapt to a color cast quickly, and laptop and phone displays disagree about black level and gamma. A scope does neither, which is why colorists trust it over any single monitor.
Why “Cinematic” Usually Means Less
Phone footage defaults to high saturation, hard contrast and crushed blacks so it looks punchy on a small screen. Film behaves differently: a projected print never reaches true black, and film rolls off gently into its highlights instead of clipping. So the common cinematic recipe is restraint: trim saturation, lift the blacks slightly, add a gentle S-curve, and often push the shadows cool while keeping skin warm, the teal-and-orange look. A grade can’t add lighting that wasn’t there; mostly it takes away the aggressive defaults.
How Valmera Grades
In Valmera you describe the look and the AI agent sets the grade: one of six presets (vibrant, warm, cool, black and white, vintage, cinematic) plus custom exposure, contrast, saturation, temperature, tint, shadows and highlights on top. Shadows and highlights are curve controls, so lifting the shadows raises the black point while middle grey stays put: the faded-print look rather than a brighter picture. Captions and graphics are never graded, and the agent checks frames of the preview before it replies.
The scope is one primary grade for the whole video: no per-shot matching, no qualifiers or power windows, no scopes, and no .cube LUT import or log conversion. For that work, use a dedicated grading app, or convert log footage before uploading. To try looks on your own clip, use the free browser preview on the AI color grading page.
Related Terms
Other entries in the Valmera video editing glossary:
- Shot detection: finding the cuts a per-shot grade would need.
- Edit decision list: where a grade lives as a reversible decision rather than baked pixels.
- Proxy editing: judging a grade on a light copy, then rendering it from the original.
- Burned-in captions vs subtitles: why text should be burned in after the grade, not under it.
Frequently Asked Questions
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