Color Grading Wheel

Definition

The Color Wheel is a method in modern color correction and grading software. It provides an intuitive, circular control interface where:

• Angle: Determines the hue - from red through yellow, green, cyan, blue to magenta
• Radius (Distance): Determines the saturation - from neutral in the center to maximum saturation at the edge
• Center: Black point for neutral, desaturated color

The color wheel enables simultaneous adjustment of hue and saturation in a visual interface, allowing more intuitive work than separate RGB sliders.

Historical Context

Origins in Analog Technology

The color wheel concept stems from analog television production:

• 1960s: Analog colorizer devices with mechanical wheels
• 1980s: Digital transition with first software-controlled wheels
• 2000s: DaVinci and other grading systems perfect the interface

Modern Software Implementation

DaVinci Resolve (since v12):

• Three wheels: Shadows, Midtones, Highlights
• Lift/Gamma/Gain Model
• Offset/Power/Slope Model

Adobe Premiere/AE (Lumetri):

• Simple wheel interface
• Curve-based implementation

Final Cut Pro:

• Color Wheels since 10.4.1
• Simplified interface similar to DaVinci

Technical Operation

Mathematical Foundations

The color wheel is based on HSL or HSV color space:

HSL (Hue, Saturation, Lightness)
- Hue: 0-360 degrees (angle)
- Saturation: 0-100% (radius)
- Lightness: 0-100% (separate dimension)

RGB to HSL Conversion:

Max = max(R, G, B)
Min = min(R, G, B)
L = (Max + Min) / 2

S = 0 (if L = 0 or 1)
S = (Max - Min) / (2 - Max - Min) (if L > 0.5)
S = (Max - Min) / (Max + Min) (if L ≤ 0.5)

H = 0 (if Max = Min)
H = 60 * ((G - B) / (Max - Min)) + 0 (if Max = R)
H = 60 * ((B - R) / (Max - Min)) + 120 (if Max = G)
H = 60 * ((R - G) / (Max - Min)) + 240 (if Max = B)

Visual Representation

Color Wheel Arrangement:

 Red (0°)
 |
Magenta--|--Yellow
 |
 Cyan (180°)

Standard HSL Color Wheel:

• Red: 0°
• Yellow: 60°
• Green: 120°
• Cyan: 180°
• Blue: 240°
• Magenta: 300°

Lift / Gamma / Gain Model

The classic color wheel model in DaVinci uses Lift/Gamma/Gain:

Shadows Wheel (Lift)

Definition:

• Adjusts the darkest pixels (black point)
• Black Lift: Raises the blacks (less contrast, milkier)
• Adding color: Tints the shadows

Practical Application:

• Lift Red: Shadow area becomes reddish
• Lift Cyan: Shadow area becomes blue-green
• Lift in the center: Neutral brightening

Grading Tips:

• Usually adjust very subtly
• Too much lift leads to a "flat" image
• Often used for skin tone calibration

Midtones Wheel (Gamma)

Definition:

• Adjusts mid-tone values (18% gray)
• Largest impact on visual perception
• Color cast is most visible in midtones

Practical Application:

• Gamma Red: Midtones become warmer (reddish)
• Gamma Cyan: Midtones become cooler (bluish)
• Greatest creative flexibility

Grading Tips:

• Strongest visual effect
• Skin tones usually adjusted via gamma wheel
• Most creative work happens here

Highlights Wheel (Gain)

Definition:

• Adjusts the brightest pixels (white)
• Affects specular highlights and bright objects
• Often subtle for premium grading

Practical Application:

• Gain Red: Highlights become warmer
• Gain Blue: Highlights become cooler
• Frequently adjusted for practical light/candlelight

Grading Tips:

• Caution: Overly aggressive changes look unnatural
• Often used for creative looks (e.g., orange-blue contrast)
• Color temperature adjustment

Workflows with Color Wheels

Scenario 1: White Balance Correction

Shot under artificial light (tungsten, 3200K) instead of daylight (5600K):

On Set (with monitoring software):

1. Look at color wheel
2. Color is too warm/reddish
3. Shift Gamma wheel toward Cyan
4. Until skin and whites look natural

In Grading:

1. Open DaVinci
2. Use Midtones Wheel (Gamma)
3. Shift toward Cyan until white point is correct
4. Optionally reference with eyedropper on white

Scenario 2: Creative Color Grading

Warm, orange-tinted scene (e.g., sunset, bar):

Process:

1. Shadows (Lift Wheel): Add slight warmth (orange)
2. Midtones (Gamma Wheel): Stronger warmth for main effect
3. Highlights (Gain Wheel): Optionally cool (blue) for contrast

Result: Warm shadows and midtones, cool highlights (orange-blue contrast)

Scenario 3: Skin Tone Matching

Multiple actors in different lighting situations:

1. Reference Shot: Establish skin tone as reference
2. Other Shots: Match against reference using Gamma wheel
3. Wheel Position: Should be similar for all
4. Tracking: Notes for consistency across takes

Offset / Power / Slope Model

Alternatively, some systems use Offset/Power/Slope:

DaVinci Resolve Advanced Controls

Offset:

• Additive color correction
• Similar to Lift, but with different mathematics
• Affects all tonalities evenly

Power:

• Multiplicative correction
• Exponential effect on brightness
• Similar to Gamma, but not identical

Slope:

• Contrast adjustment
• Steepening of the curve
• Useful for tone separation

Practical Grading Tips with Color Wheels

Rule 1: Cool Shadows, Warm Highlights

Classic cinema grading:

• Shadows (Lift): Slightly cyan/blue
• Highlights (Gain): Slightly warm/orange
• Creates emotional contrast and depth

Rule 2: Skin Tones via Midtones Wheel

• Skin tone sensitivity is highest in the midtones
• Most adjustment should happen here
• Dose shadows and highlights more finely

Rule 3: Saturation Before Color Grading

Workflow:

1. First set exposure/contrast correctly (with curves)
2. Then add color via color wheels
3. Don't adjust saturation and hue extremely at the same time

Rule 4: Less Is More

• Color wheel adjustments are very visually obvious
• Subtle adjustments (small radius movements) look more realistic
• Too much color grading looks artificial and "graded"

Common Mistakes and Corrections

Integration with Other Grading Tools

Relationship to Curves

Color Wheel (fast, intuitive):

• Perfect for quick adjustments
• Good feel for direction
• Limited precision

Curves (precise, detailed):

• Fine control over tone curve
• Individual RGB channels adjustable
• More time-consuming, but higher control

Combination:

1. Initial adjustment with color wheel (find direction)
2. Fine-tuning with curves (precision)

Relationship to HSL/Saturation Controls

Color Wheel:

• Adjusts colors in shadows/midtones/highlights
• Hue + saturation in one movement

HSL Saturation Controls:

• Saturation global or per hue range
• For specific color correction

Workflow:

1. Color wheel for overall mood
2. HSL for selective color adjustment (e.g., saturate only reds)

Monitoring and Visualization

Scope Tools for Color Wheel Control

Vectorscope:

• Shows color position on the wheel
• Helps verify white balance
• Is a 2D projection of color wheel space

Parade:

• Shows RGB channels separately
• Check if red/green/blue are balanced
• Complementary to color wheel

Waveform Monitor:

• Shows brightness (tonality)
• Complementary to color wheel (shows color)
• Together both tools provide complete control

Summary

The color wheel is the most intuitive and fastest tool for color correction in modern grading software. The combination of hue selection (angle) and saturation (radius) enables quick, effective adjustments. Professional colorists use color wheels as the first quick tool before more precise adjustments with curves and other controls. Understanding the Lift/Gamma/Gain model is essential for professional grading.