Keying: Composite Controls

The Composite Controls incorporate some of the color correction and advanced compositing features found in Red Giant Software’s Key Correct™ plug-in suite for After Effects. There are three main components to the Composite Controls.

• Spill Killer

• Color Matcher

• Light Wrap

BG Layer

The BG Layer (Background Layer) is a global option set for all Composite Control options. It determines the layer that will be used in the Color Matcher and Light Wrap functions. Drag and drop your background clip into the small box on the right hand side of the BG Layer area.

Spill Killer

As its name suggests, Spill Killer is a spill removal filter. It operates completely separately from the spill suppression functions within the Primatte algorithm itself. It can be used in conjunction with Primatte’s spill removal functions, or on its own. The determination on which to use will be dependent on the specifics of each individual shot.

Spill Killer mathematically analyzes and corrects for colored spill on the foreground element, caused by bounced light from the surface of the bluescreen without harming the original color of the pixels. Spill Killer will also correct many spill situations that might otherwise be difficult, on semi-transparent areas like fringe and motion blur. Consider the following bluescreen element directly below...

...and the keyed footage below, which has a significant amount of blue spill.

Enable Spill Killer

The enable checkbox allows you to enable or disable the Spill Killer tool. It is off by default.

Color Mode

The Color Mode pop-up allows you to choose the default spill removal color. Choose between Red, Green, and Blue.

Range

The Range slider allows you to specify the lower value, designating which pixels will be corrected. The lower the setting, the more pixels will be affected. Range also defines the limit of spill suppression. The lower the setting, the more correction will occur.

Tolerance

The Tolerance slider controls the upper value, defining which pixels will be corrected. The higher the setting, the more pixels will be corrected. In most cases, a setting of 100% is recommended. Strength The Strength slider determines how much the original colors of the foreground element are spill corrected. A value of 100% means that the foreground colors are completely corrected.

Strength

The Strength slider determines how much the original colors of the foreground element are spill corrected. A value of 100% means that the foreground colors are completely corrected.

Color Matcher

One of the biggest problems that arises when compositing a shot comes in making the foreground and background elements appears as if they coexist in the same space. Balancing an element’s tonal exposure to make it fit into a new environment can often involve multiple applications of standard color correction filters.

Color Matcher enables you to easily integrate an element into a composite environment by balancing the element’s colors to match the general color balance of the environment into which it is being placed. This is accomplished quickly, and with just a few mouse clicks can yield results superior to those achieved with hours of work with conventional color correction filters.

Users of versions of Color Matcher on other applications will notice a significantly improved interface. The new algorithm automatically samples the specified background layer and remaps the foreground to match. In addition, you now have far greater control over the color correction process with the introduction of individual RGB controls for shadow, midtone, and highlight ranges.

Enable Color Matcher

This checkbox allows you to enable or disable the Color Matcher tool. It is off by default.

Strength

The Strength slider determines how much the original colors of the foreground element are adjusted towards the background colors. A value of 100% means that the foreground colors are completely replaced.

The image below shows a Strength value of 25%.

The image below shows a Strength value of 75%. The color remap can be as subtle or as bold as you choose.

Highlights/Midtones/Shadows

These three sets of sliders, as their names suggest, allow you to color correct the highlight, midtone, and shadow ranges of the image. Each tonal range offers a set of RGB sliders, enabling you to add or remove red, green, or blue in each range to achieve the highest quality match.

Light Wrap

Light Wrap is the secret to seamless layer integration. It works by wrapping the edges of a foreground layer with soft light from the background layer, producing a powerful level of integration by providing the illusion that light from the background layer is reflecting along the edges of the foreground.

Enable Light Wrap

This Enable checkbox allows you to enable or disable the Light Wrap tool. It is off by default.

Operation

The Operation pop-up determines the output from Light Wrap. There are three modes...

Comp on Background is the default output, and the one you will use most of the time. It displays the light-wrapped foreground composited over the background element.

The image below shows the keyed and color corrected foreground,

The image below shows the same image with Light Wrap applied In this mode the output alpha channel is solid white.

Wrap Only displays only the background; the foreground element disappears. However, the edge area is placed in the matte. This mode allows you to set up the Light Wrap effect as a separate element, which can be rendered out on its own to be used in another composite.

The image below shows the RGB channel generated when this mode is selected.

The image below shows the Alpha channel generated when this mode is selected.

Wrap on Black works virtually identically to the Wrap Only mode, except it pre-composites the masked RGB layer over black and renders it out with a solid white alpha. The output from this mode allows you to bring in the element and composite it over the background by setting its transfer mode to Screen.

Background Blur

The Background Blur slider designates the amount of internal blur applied to the background image before the light wrap effect is applied. This is a pre-process only; it merely softens the wrap effect, and will not alter the background element in any way.

Comp Mode

The Comp Mode menu determines the compositing mode used in Light Wrap. These modes are identical in function to the transfer modes found in Final Cut Pro. For detailed explanations of these transfer modes, please refer to your Final Cut Pro documentation.

Width

The Width value controls the width of the light wrap effect. Higher settings create a bigger backlight wrap on the layer. The Width value operates independently of Background Blur, allowing you to set a high blur value on the background element while still retaining independent control of the width of the effect.

Brightness

As its name suggests, Brightness controls how bright the wrap effect will be. Higher settings are brighter, negative numbers are darker.