Response curves represent the noise intensity for each colour channel. Modify the red, green, or blue response curves to fine-tune the degrain. You can add vertices to a curve to refine your adjustments.

To modify the red, green, or blue curve:

1. To display the response curve, click Show Curves.
2. Show the response curve you want to modify by clicking the button corresponding to the colour of the curve.

   The selected curve is highlighted.

3. Sample the colour you want to use as a reference for your adjustments.

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

4. Do one of the following:
   • 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.
5. 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.
6. 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.