Composite Modes in Final Cut Pro

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′CBCR 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′CBCR 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.

Important: Final Cut Pro composite modes work in conjunction with a clip’s Opacity parameter. The composite mode you select determines how the color values of one clip interact with those in the clip beneath it. Additional changes made to a clip’s opacity can lighten or intensify this effect.

Applying Composite Modes to Clips

Applying different composite modes to layered clips in a sequence is easy. The main thing to remember is that composite modes affect the interaction between one layered clip and whichever clip is underneath it in the sequence. Clips that are above a layered clip using a composite mode are unaffected.

You can quickly view or change a clip’s composite mode while working in the Timeline. This provides a fast alternative to choosing a different composite mode from the Modify menu.

About the Examples in This Section

Most of the examples in this section combine the following two reference images to create a third composite image. The composite image illustrates how the color values from each image interact when using each composite mode. When examining the results, pay particular attention to the white and black areas of the colored squares, as well as the highlights and shadows in the monkey image. These show you how each composite mode treats the whites and blacks in an image.

The other brighter and darker colors serve to illustrate each composite mode’s handling of overlapping midrange color values. The yellow, gray, orange, and blue squares, in particular, all have very different color and luma values that contrast sharply from example to example.

Important: Depending on the composite mode, layer ordering may or may not be important. Certain composite modes behave differently depending on which image is on top.

Normal

Normal is the default composite mode for clips. When a clip uses Normal composite mode, you can still adjust its transparency by using its Opacity parameter or an alpha channel.

Add

Add emphasizes the whites in each overlapping image, lightening all other overlapping colors. The color values in every overlapping pixel are added together. The result is that all overlapping midrange color values are lightened. Blacks from either image are transparent, while whites in either image are preserved.

The order of two clips affected by the Add composite mode does not matter.

Suggested uses: The Add composite mode is useful for using one image to selectively add texture to another, based on its lighter areas such as highlights. You can also use Lighten and Screen to create variations of this effect.

Subtract

Subtract darkens all overlapping colors. Whites in the foreground image go black, while whites in the background image invert overlapping color values in the foreground image, creating a negative effect.

Blacks in the foreground image become transparent, while blacks in the background image are preserved.

Overlapping midrange color values are darkened based on the color of the background image. In areas where the background is lighter than the foreground, the background image is darkened. In areas where the background is darker than the foreground, the colors are inverted.

The order of two clips affected by the Subtract composite mode is important.

Difference

The Difference composite mode is similar to the Subtract composite mode, except that areas of the image that would be severely darkened by the Subtract composite mode are colored differently.

The order of two clips affected by the Difference composite mode does not matter.

Multiply

Multiply emphasizes the darkest parts of each overlapping image, except that midrange color values from both images are mixed together more evenly. Progressively lighter regions of overlapping images become increasingly translucent, allowing whichever image is darker to show through. Whites in either image allow the overlapping image to show through completely. Blacks from both images are preserved in the resulting image.

The order of clips affected by the Multiply composite mode does not matter.

Suggested uses: The Multiply composite mode is particularly useful in situations where you want to knock out the white areas of a foreground image and blend the rest of the image with the colors in the background. For example, if you superimpose a scanned sheet of handwritten text over a background image using the Multiply composite mode, the resulting image becomes textured with the darker parts of the foreground.

Screen

Screen emphasizes the lightest parts of each overlapping image, except that the midrange color values of both images are mixed together more evenly.

Blacks in either image allow the overlapping image to show through completely. Darker midrange values below a certain threshold allow more of the overlapping image to show. Whites from both images show through in the resulting image.

The order of two clips affected by the Screen composite mode does not matter.

Suggested uses: The Screen composite mode is especially useful for knocking out the blacks behind a foreground subject and is an alternative to using a luma key. Screen is mainly useful when you want the rest of the foreground subject to be mixed with the background image as well, based on its brightness. It’s good for glow and lighting effects, and for simulating reflections. You can also use the Add and Lighten composite modes to create variations of this effect.

Overlay

Whites and blacks in the foreground image become translucent and interact with the color values of the background image, causing intensified contrast. Whites and blacks in the background image, on the other hand, replace overlapping areas in the foreground image.

Overlapping midrange values are mixed together differently depending on the brightness of the background color values. Lighter background midrange values are mixed by screening. Darker background midrange values, on the other hand, are mixed together by multiplying.

The visible result is that darker color values in the background image intensify overlapping areas in the foreground image, while lighter color values in the background image wash out overlapping areas in the foreground image.

The order of two clips affected by the Overlay composite mode is important.

Suggested uses: The Overlay composite mode is particularly useful for combining areas of vivid color in two images.

Hard Light

Whites and blacks in the foreground image block overlapping areas in the background image. Whites and blacks in the background image, on the other hand, interact with overlapping midrange color values in the foreground image.

Overlapping midrange color values are mixed together differently depending on the brightness of the background color values. Lighter background midrange values are mixed by screening. Darker background midrange values, on the other hand, are mixed together by multiplying.

The visible result is that darker color values in the background image intensify overlapping areas in the foreground image, while lighter color values in the background image wash out overlapping areas in the foreground image.

The order of two clips affected by the Hard Light composite mode is important.

Soft Light

The Soft Light composite mode is similar to the Overlay composite mode. Whites and blacks in the foreground image become translucent but interact with the color values of the background image. Whites and blacks in the background image, on the other hand, replace the overlapping areas in the foreground image. All overlapping midrange color values are mixed together, creating a more even tinting effect than that created by the Overlay composite mode.

The order of two clips affected by the Soft Light composite mode is important.

Suggested uses: The Soft Light composite mode is useful for softly tinting a background image by mixing it with the colors in a foreground image.

Darken

Darken emphasizes the darkest parts of each overlapping image. Whites in either image allow the overlapping image to show through completely. Lighter midrange color values become increasingly translucent in favor of the overlapping image, while darker midrange color values below a certain threshold remain solid, retaining more detail.

The order of two clips affected by the Darken composite mode does not matter.

Suggested uses: The Darken composite mode is useful for using one image to add texture to another selectively, based on its darker areas. You can also use Screen for variations on this effect.

Lighten

Lighten emphasizes the lightest parts of each overlapping image. Every pixel in each image is compared, and the lightest pixel from either image is preserved, so that the final image consists of a dithered combination of the lightest pixels from each image. Whites in both images show through in the resulting image.

The order of two clips affected by the Lighten composite mode does not matter.

Travel Matte – Alpha

When you apply the Travel Matte – Alpha composite mode to a selected clip, the alpha channel from the clip below is applied to the selected clip. Only two clips are required to use this composite mode, but in most situations, you will use three layers:

• Foreground (top layer): This layer appears on top of the background layer, as seen through the alpha channel. Apply the Travel Matte – Alpha composite mode to this layer.
• Alpha channel (middle layer): This layer provides the alpha channel (transparency information) for the foreground layer.
• Background (bottom layer): This optional layer appears beneath the foreground image wherever the foreground image is masked by the alpha channel. The background can be a single layer, or multiple layers blended with transparency or composite modes. If no background layer exists, the Canvas displays the default Final Cut Pro background color (checkerboard, black, white, and so on), and black appears during output and export.
  

Travel Matte – Luma

The Travel Matte – Luma composite mode does the same thing as the Travel Matte – Alpha composite mode, but the transparency is derived from the luma information (instead of the alpha channel) of the clip below. The luma information may be derived from a grayscale equivalent of the RGB channels, or directly from the luma (Y′) channel in the case of Y′CBCR video. White is equal to 100 percent transparency and black is equal to 100 percent opacity (solid).