Comprehensive Guide to DaVinci Resolve's 7 Curve Tools for Professional Color Grading

Cullen Kelly

Curves Panel Overview [00:15]

This video provides an overview of all 7 curve tools in DaVinci Resolve's color page, designed to enhance color grading skills and image manipulation. The "Custom Curves" tool is introduced first but is discussed later as it operates differently from the other "versus" tools.

Understanding the "Versus" Curves Logic (The X vs Y Rule) [01:03]

The video establishes a simple rule for all "versus" curve tools to easily identify their function:

• The second term in the "A versus B" convention indicates what you are changing (the output or Y-axis manipulation).
  • For example, in "Hue vs Lum," you are changing Luminance.
• The first term indicates the basis on which you are making the adjustment (the input or X-axis range).
  • For example, in "Hue vs Lum," you are changing luminance based on Hue.
• All "versus" tools operate like an X versus Y graph, where the horizontal line represents no change, meaning the output matches the input.

  

  • Adjustments are made within specific input ranges to modify the output.
  • This logic makes the curve tools a powerful form of secondary grading, allowing adjustments to a portion of the image based on color.

    

1. Hue vs Hue Curves [04:10]

This tool adjusts the Hue of an image based on its existing Hue.

• Practical Application:
  • Presets are available for primary and secondary colors (red, green, blue, cyan, magenta, yellow).
  • Using a preset, like yellow, creates "goalposts" and a center control point for adjustment.
  • Dragging the center point up or down rotates the hue (e.g., making yellows more green or red).
  • The vector scope visually confirms the hue rotation.
• Avoiding Image Breakage with Narrow Adjustments [06:49]
  • Broad adjustments, like those from presets, generally result in cleaner changes.
  • Narrower selections, made by eyedropping specific areas (e.g., skin tone), are more sensitive.
  • Aggressive adjustments to narrow selections can "break" the image, introducing artifacts or "chatter."
  • Best Practice: Aim for the broadest possible adjustment without affecting unintended areas.
  • If a narrow selection is necessary, the goalposts can be manually widened by dragging them left or right.
    • After widening, it's crucial to manually key in '0' for the output values of the goalpost control points to ensure no unintended global hue rotation.
  • A single control point without goalposts will rotate the hue of the entire image, similar to a primary adjustment.

    

Additional Features of Curve Tools [08:19]

• Editable Splines & "Big Curves Mode" [10:15]
  • The "Editable Splines" button allows for finessing the curve's shape between control points, useful for subtle, fine-tuned adjustments.
  • The "Big Curves Mode" (activated by the four-way arrow) expands the curve graph, making it easier to see and manipulate splines and control points with greater precision.

    

  • These features are consistent across all "versus" curve tools.

2. Hue vs Sat Curves [11:07]

This tool adjusts the Saturation of an image based on its Hue.

• Understanding Hue Input: The horizontal X-axis displays a rainbow of hues, representing a continuous circle. Adjustments to red, for instance, might wrap around the left and right edges of the graph.
• Practical Application:
  • Eyedropping a specific color, like skin tone, allows for selective saturation or desaturation of that hue range.
  • Increasing the control point within the defined goalposts boosts saturation only for those specific hues.

    

3. Hue vs Lum Curves [13:15]

This tool adjusts the Luminance (brightness) of an image based on its Hue.

• Practical Application:
  • Useful for selectively brightening or darkening specific colors in the image.
  • For example, eyedropping a color patch and pulling the control point down will darken only that color.

    

Using the Histogram in Curves [14:07]

All "versus" curve tools include a histogram underlaying the graph.

• The histogram visually represents the distribution of image information within the input channel (e.g., Hue, Luminance, Saturation).
• Peaks indicate areas with high concentrations of image data.
• Assessing Potential Image Breakage [14:57]
  • Making adjustments in areas with very little image data on the histogram will likely have minimal effect.
  • Placing goalposts directly on sharp peaks or valleys of the histogram increases the risk of introducing noise or artifacts, as you are creating a stark separation between included and excluded data.

4. Lum vs Sat Curves [15:28]

This tool adjusts the Saturation of an image based on its Luminance.

• Luminance as Input: The X-axis represents a grayscale gradient, from dark blacks on the left to bright whites on the right.
• Practical Application:
  • Desaturating Highlights: Pulling down the control point on the right (bright areas) reduces the saturation of bright parts of the image to zero.
  • Saturating Shadows: Boosting the control point on the left (dark areas) increases the saturation of shadow areas.
  • Control Points: As with other curves, multiple control points can be used to create complex curves, but it is recommended to use the bare minimum needed to avoid unwanted artifacts and maintain efficiency.

    

5. Sat vs Sat Curves [17:22]

This tool adjusts the Saturation of an image based on its own Saturation level.

• Practical Application:
  • Boosting Low Saturations: Raising the control point on the left (less saturated areas) increases their saturation.
  • Reducing High Saturations: Lowering the control point on the right (most saturated areas) desaturates them.

    

6. Sat vs Lum Curves [18:15]

This tool adjusts the Luminance of an image based on its Saturation.

• Getting Filmic Saturation [18:38]
  • A common use is to achieve a "filmic" look where more saturated colors tend to be darker.
  • By pulling down the control point on the right side of the curve (highly saturated areas), colorful elements become darker. This acts like a gain adjustment applied selectively to areas with high color.

    

Advanced Histogram Monitoring [19:14]

• The histogram display can be toggled between "Input" and "Output" modes via the three-dot menu.
• Input Mode: Shows the histogram of the original image data.
• Output Mode: Shows how the histogram changes as you make adjustments to the curve, reflecting the real-time modified image data.

7. Custom Curves [20:35]

The Custom Curves tool is distinct from the "versus" curves and is considered a powerful primary grading tool.

• Unique Characteristics:
  • It does not explicitly use the "versus" naming convention, though it functions conceptually as a "Luminance vs Luminance" curve.
  • The default "no change" line is a diagonal line from bottom-left to top-right, unlike the flat horizontal line of "versus" curves.
• Primary Adjustment Focus:
  • While it can make localized adjustments, its primary strength lies in global luminance and color adjustments.
  • It offers a more finessed control over traditional Lift, Gamma, and Gain controls found in the primaries palette. For example, lifting the bottom control point performs a "lift" adjustment, but with the ability to reshape the curve in ways not possible with primary wheels.

    

• Advanced Control:
  • Provides more degrees of freedom than primary controls, allowing for unique curve shapes to finely sculpt the image's tonal response.
  • Can manipulate not just all three Red, Green, and Blue channels together, but also individual Red, Green, and Blue channels.
  • Features like "Option-click to pin a control point to the unity line" offer further precise control.

    

• Trade-off: Offers greater control and finesse but is generally slower to manipulate compared to the speed of primary color wheels. It's invaluable for shots requiring precise tonal shaping.