Motion 5 - Color Balance

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Color Balance

Color balance refers to the relative strength of the red, green, and blue channels that
constitute an image. For example, a blue-tinted image has a strong blue channel and
weaker green and red channels.

The Color Balance filter lets you adjust the relative balance of all three color channels of
an image at once—for example, lowering the blue channel and raising the red and green
channels to reduce blue tinting and yield an image that appears more orange and warm.

Color balance also relates to color temperature, which describes the quality of light in an
image. For example, sunlight is generally more bluish than tungsten light, which is more
orange. In professional film and video productions, white-balancing the camera before
shooting usually ensures that whites in an image are neutral (with all three color channels
balanced evenly). However, film stocks, optical filters, and digital white-balance settings
can modify the tint of an image.

Note: The imbalanced color channels caused by a dominant color temperature in the
lighting of an image is often referred to as a color cast.

You can use the Color Balance filter to adjust the three color channels of an image to
eliminate a color cast or introduce one. Here are some uses for the Color Balance filter:

• To correct problems in lighting—for example, rebalancing an image that’s too orange

to appear more neutral.

• To match two images to one another—for example, matching the quality of light on

an actor in a foreground green screen clip to the lighting in a background image.

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• To stylize the color of an image used in a creative composition—for example, creating

a high-contrast, blue-tinted silhouette from the image of two actors dancing for a title
sequence.

The Color Balance filter doesn’t just let you rebalance the overall strength of an image’s
three color channels, it also lets you rebalance color specifically in three tonal zones of
an image: shadows, midtones, and highlight. Three correspondingly named color controls
let you make color balance adjustments in each zone of image tonality.

To make an adjustment to a zone, click the corresponding color well to open the Mac OS
Colors window, then drag in the color wheel. As you drag, the image updates. Dragging
in a specific hue’s direction rebalances the image, tinting it with that hue. The farther
towards the edge of the color wheel you drag, the more intensely you tint the image.

Tip: You can use any controls in the Mac OS X Colors window to make color adjustments,
including sliders, web-safe colors, and the magnifying glass picker. Further, you can save
frequently used tints by dragging a color from the color bar at the top to an empty white
swatch below. Clicking a filled swatch selects that color.

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The adjustments to shadows, midtones, and highlights of an image overlap widely. For
example, adjustments to shadows affect the darkest parts of the image the most, but the
effect also influences midtones and lower highlights. This overlap ensures that adjustments
you make blend seamlessly with the original colors of the image.

For a practical example of using the Color Balance filter, see

Matching Two Composited

Layers Using the Color Balance Filter

.

Note: Although you can make small contrast adjustments using the vertical lightness
slider in the color wheel pane of the Colors window, it’s better to use the Contrast or
Levels filters to make adjustments to the overall lightness and darkness of an image.

Parameters in the Inspector

Shadows:

Adjusts color channels in the darkest regions of the image. Click the color well

to open the Colors window, then adjust the color balance of the darkest portion of the
image. An eyedropper lets you sample any color in the Canvas to use for balancing the
image. You can also click the disclosure triangle to reveal individual red, green, and blue
channel sliders, with a numeric range from 0 (no color) to 0.5 (unaltered color) to 1.0
(maximum color).

Red: Adjusts the color gain applied to the shadow range of the red color channel.

Green: Adjusts the color gain applied to the shadow range of the green color channel.

Blue: Adjusts the color gain applied to the shadow range of the blue color channel.

Midtones:

Adjusts color channels in midtone regions of the image. Click the color well

to open the Colors window, then adjust the color balance of the range of color falling
between shadows and highlights. An eyedropper lets you sample any color in the Canvas
to use for balancing the image. You can also click the disclosure triangle to reveal red,
green, and blue channel sliders with a numeric range from 0 (no color) to 0.5 (unaltered
color) to 1.0 (maximum color).

Red: Adjusts the color gain applied to the midtone range of the red color channel.

Green: Adjusts the color gain applied to the midtone range of the green color channel.

Blue: Adjusts the color gain applied to the midtone range of the blue color channel.

Highlights:

Adjusts color channels in the lightest regions of the image. Click the color

well to open the Colors window, then adjust the color balance of the brightest portion
of the image. An eyedropper lets you sample any color in the Canvas to use for balancing
the image. You can also click the disclosure triangle to reveal red, green, and blue channel
slider with a numeric range from 0 (no color) to 0.5 (unaltered color) to 1.0 (maximum
color).

Red: Adjusts the color gain applied to the highlights of the red color channel.

Green: Adjusts the color gain applied to the highlights of the green color channel.

Blue: Adjusts the color gain applied to the highlights of the blue color channel.

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Clip Color Values:

Turns clipping on and off. Clipping prevents color adjustments from

forcing color values out of the allowable digital range. Clipping can prevent illegal signal
levels in clips that are output to video. This pop-up menu has four options:

None: No clipping occurs.

At White: Any color channel exceeding the maximum value of 1 is clipped to 1.

At Black: Any color channel falling below the minimum value of 0 is clipped to 0.

At Black and White: All color channels are clipped to a minimum of 0 and a maximum

of 1.

Mix:

Sets the percentage of the original image to be blended with the color-corrected

image.

HUD Controls
The HUD contains the following controls: Shadows, Midtones, Highlights, and Clip Color
Values.