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Using ColorCorrect Sliders

The ColorCorrect node is particularly convenient for making quick adjustments to contrast, gamma, gain, and offset. A single window houses sliders for all these basic corrections and allows you to apply these to a clip’s master (entire tonal range), shadows, midtones, or highlights.

To Adjust Contrast, Gain, Gamma or Offset with the ColorCorrect Node

1.   Click Color > ColorCorrect (or press C) to insert a ColorCorrect node at the appropriate place in your script.
2.   Connect a Viewer to the output of the ColorCorrect node so you can see the effect of your changes.
3.   In the ColorCorrect properties panel, use the channels dropdown menu to select the channels you wish to process.
4.   Drag the slider appropriate to the region you want to affect an operation you want to apply.

For example, to brighten the images highlights, you would drag on the highlights gain slider.

Remember too that you can use the color sliders to apply any of the corrections on a per channel basis.

5.   On the Ranges tab, enable test to show what is considered to be in the shadows, midtones, or highlights.

This overlays the output with black (for shadows), gray (for midtones), or white (for highlights). Green and magenta indicate a mixture of ranges.

Original image. The same image with test enabled.
6.   Still on the Ranges tab, you can use the shadow and highlight lookup curves to edit the range of the image that is considered to be in the shadows or highlights. You can also look up color information for the current pixel in the Viewer.

To return a curve to its default values, select it and click reset.

WARNING:  Do not adjust the midtone curve. Midtones are always equal to 1 minus the other two curves.

7.   To control how much of the original luminance is preserved after the color correction, enable and adjust mix luminance. A value of 0 means the altered luminance is used in the output image. A value of 1 produces a luminance value close to that of the original input image.
Original image.
Mix luminance set to 0. Mix luminance set to 1.

NOTE:  When mix luminance is set to 1, the resulting luminance value is close to the original luminance, but not exactly the same. The difference may vary depending on the color corrections applied to the source image.

Adjusting Black Levels with the Toe Node

Toe lifts the black level, in a similar way to gain controls, but with a roll-off so that whites are mostly not affected.

1.   Click Color > Toe to create a Toe node. Connect it to the image whose black levels need adjusting.
2.   Adjust the lift slider to change the black values to the specified gray value, without affecting any original white values of the image.
3.   If necessary, you can limit the effect to a particular channel with the channels controls.
4.   If you need to, you can pick a channel in the (un)premult by dropdown to divide the image first with that channel and then multiply it again afterward. Doing this can sometimes improve your color correction results on anti-aliased egdes.
5.   You can also use the mix control to dissolve between the original input (value 0) and the full effect of the Toe node (value 1). If you only want to use one channel for mixing, you can specify that using the mask control.