Working with composite modes, How composite modes affect images, P. 393) – Apple Final Cut Pro 6 User Manual

Page 1178

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Chapter 19

Compositing and Layering

393

II

Working with Composite Modes

Final Cut Pro composite modes determine how the brightness and color of one clip
visually interact with those of another clip layered beneath it in a sequence. When you
edit a clip into your sequence, it defaults to the Normal composite mode, meaning that
it is a completely opaque layer that does not blend with the layers beneath.

How Composite Modes Affect Images

Composite modes mix colors from overlapping images together based on the
brightness values within each color channel in an image. Every image consists of red,
green, blue, and alpha channels (or one luma and two chroma channels in the case of
Y´C

B

C

R

component video). Each individual channel contains a range of brightness

values that defines the intensity of each pixel in the image that uses some of that color.

The effect that each composite mode has on objects that overlap in the Canvas
depends on the range of color values within each object. The red, green, and blue
channels (or Y´C

B

C

R

channels) within each overlapping pixel are mathematically

combined to yield the final image.

These value ranges can be described as blacks, midrange values, or whites. These
regions are loosely illustrated by the chart below.

For example, the Multiply composite mode renders color values that fall into the white
areas of an image transparent, while the black areas of the image are left alone. All
midrange color values become translucent, with colors falling into the lighter end of the
scale becoming more transparent than the colors that fall into the darker end of the scale.

Blacks

Whites

Midrange color values

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