Plotting Colour Values when Adjusting Curves			Modifying Hue, Saturation, Luminance, and Lightness
Chapter 14, Colour Grading: RGB and Hue Curves

Modify the RGB, red, green, or blue curves to fine-tune the colour grade. When you modify the RGB curve, the red, green, and blue channels are adjusted equally. When you modify the red, green, or blue curve, only the selected colour channel is adjusted. You can add vertices to a curve to refine your adjustments.

1. Indicate the colour grading stage at which the curve modification is being applied:

   • To work on the initial primary grade, click Input.

   • To make final adjustments to the primary grade, click Output.

   • To make curve modifications for secondary colour grading, enable a secondary layer.

2. Click RGB to display the RGB curves.

   

3. Show the curve you want to modify by clicking the button corresponding to the colour of the curve.

   The selected curve is highlighted.

   Note: To display the RGB curve, click the white button.

   

4. Sample the colour you want to use as a reference for your adjustments. See Plotting Colour Values when Adjusting Curves.

   Red, green, and blue vertical lines representing the colour channels are plotted on the curve.

5. To add a vertex to the curve, place the mouse cursor over the area on the curve where you want to add the vertex and press A. To lock the curve in place while adding a vertex, press Shift+A on the curve.

   

6. Click a vertex to display its tangent handle and then drag the handle to adjust the curve. You can also adjust the curve by dragging the vertex.

   

7. Modify the curve until you are satisfied with the results:

   • To select a vertex, click it. To select several vertices, draw a selection box around them.

   • To move one or several selected vertices, drag a selected vertex. To restrict vertex movement to the Y axis, press Shift while moving the mouse. To restrict vertex movement to the X axis, press Shift+Alt while moving the mouse.

   • To delete vertices, select them and then press D.