Using the Remove Color Cast Buttons
You can remove a color cast automatically by clicking a Remove Color Cast button and using an eyedropper to identify an area in your image that you want to be color neutral (white, black, or a shade of gray). Avid Color Correction analyzes the current color characteristics of the area you have selected and then adjusts color correction controls to make that area color neutral.
Remove Color Cast buttons provide more precise control over color cast removal than Auto Balance buttons because their adjustments are limited either by luminance range or by the impact that they have on existing curve graphs. However, Remove Color Cast buttons are only useful when you are working with an image that has areas that should be color neutral.
Remove Color Cast buttons appear in the Color Correction tool in the following locations:
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Below each of the three ChromaWheels in the Hue Offsets subdividing
tab of the HSL tab, as shown in the following illustration:
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In the Curves tab, as shown in the following illustration:
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Each ChromaWheel Remove Color Cast button is associated with the wheel above it. Adjustments are made only to that wheel; only the parts of the image that fall within the luminance range controlled by that wheel are changed. You choose which ChromaWheel to adjust based on the luminance level of the area you want to identify, as follows:
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To make white or light gray areas of an image color neutral and
remove a cast throughout the lightest part of the image, use the
Remove Color Cast button below the Highlights ChromaWheel.
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To make mid-gray areas of an image color neutral and remove a cast
throughout the midtones of the image, use the Remove Color Cast
button below the Midtones ChromaWheel.
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To make black or dark gray areas of an image color neutral and remove
a cast throughout the darkest parts of the image, use the Remove Color
Cast button below the Shadows ChromaWheel.
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The Curves tab Remove Color Cast button works by adding a point to each of the Red, Green, and Blue curves that makes the area you identify with the eyedropper color neutral. You can use the Curves tab Remove Color Cast button repeatedly to identify multiple areas that you want to be color neutral. Each new use adds another point to each of the three curves. (You can add new points up to the 16 point limit, although once several points are distributed along the curve, further points are unlikely to improve the image significantly).
The effect of each added point on the image as a whole varies depending on the shape of the entire curve. In general, each new point affects the image most in areas with similar luminance values to the area you identify with the eyedropper, and affects the image least in areas with very different luminance values.
To use a Remove Color Cast button:
| 1. | |
If you have not already done so, move the position indicator to the
segment you want to correct.
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| 2. | |
Do one of the following:
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Click the Remove Color Cast button below a ChromaWheel in the
Hue Offsets subdividing tab of the HSL tab.
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Click the Remove Color Cast button in the Curves tab.
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The button appears highlighted.
| 3. | |
Drag the pointer into the image.
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The pointer changes to an eyedropper.
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Continue to drag the eyedropper until it is over the part of the image
you want to become color neutral, and then release the mouse button.
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Avid Color Correction analyzes the part of the image you have
identified and adjusts the controls to remove the color cast.
