BCC+ Holdout Composite
Category: BCC Key and Blend
Effect Name: BCC Holdout Composite
The BCC+ Holdout Composite filter, part of the BCC Key and Blend category, is a two-layer/track effect that effectively composites images such as fire, explosions and smoke. This filter first creates a luminance matte of the foreground and pastes it as black (or other color) over the background. You then use one of the Blend Modes to place the foreground over the โheld out backgroundโ.
To add practical fire, explosions, smoke or other footage not containing an Alpha channel is normally a challenge. A normal Math Composite Add function would cause areas of the background to get brighter. This is bad. Using a key of some type would most likely generate unwanted edge fringing. This is also bad. Holdout Composite solves these problems.Working with the Filter
FX Editor and Presets
- Use the FX Editor to load or save presets for reuse.
- To load a preset: Open the FX Editor, select a preset from the Presets panel, and click Apply to return to the host application.
- To save a custom preset: While in the FX Editor, click the Create Custom Preset icon in the parameter list, enter a preset name, and click Done. Additionally, a custom preset can be saved from the main menu bar by selecting File->Save Preset.
- To import custom presets from another drive: While in the FX Editor, select File->Import Preset from the main menu bar.
Effect Controls
Mocha Mask and Track
Continuum effects include integrated masking and matte tools that allow you to restrict the effect to specific regions of the image.
- Mocha masks: used to create custom spline masks. Mocha also includes Matte Assist ML and Matte Refine ML, which use machine learning to generate and track masks.
- Pixel Chooser: used to generate geometric shapes, gradients, or mattes based on channel, luma, or color-based selections. Additionally, an AI depth map generator, and an AI-powered face detection model allow for precise control of masks and mattes.
Note: Mocha can also be used to drive geometric parameters. See the Mocha Motion Tracker documentation for details.
For more information, see Mocha and Pixel Chooser.
Compare Mode
The Compare Mode is used to view the filtered result alongside the original source layer. Several split-screen and side-by-side display options are available.
For more information, see Compare Mode.
- View: Selects the output view for the filter.
- Output: Displays the final output for the effect.
- Foreground: Displays the foreground layer.
- Background: Displays the background layer.
- Holdout: Displays the holdout composite.
- Matte: Displays the matte used for the effect.
- Background: Selects what image to use as the background.
- Blend: Selects the type of Math Composite to use for the foreground element.
- AddThe pixels of the foreground are added to the background.
- ScreenThe foreground and background are combined using a Screen blend mode. This looks kind of like the Add blend mode, but highlights are retained.
- LightenCompares the foreground and background and takes the pixels with the higher value.
- Level: Sets the level of the foreground element.
- Black Clip: Blacks are made blacker by increasing the value of the slider. As the slider value increases, more values are clipped to black.
Note: Often times the black portion of an image is not entirely black. This becomes an issue if something like fire is shot against a black background. If the black is not entirely black, then these impure black areas will be added to the background image as part of the Holdout Composite causing the final result to have milky blacks. Black Clip will improve these milky blacks and make them darker.
Matte Group
The Holdout Composite first creates a luminance matte of the foreground and then pastes it as black (or other color) over the background. You can see the extracted matte with the View set to Matte.
- Black Clip: Blacks in the matte are made blacker by increasing the value of the slider. As the slider value increases, more values are clipped to black. This is helpful for getting rid of unwanted gray areas in what should be the black part of the matte.
- White Clip: Whites in the matte are made whiter by increasing the value of the slider. As the slider value increases, more values are clipped to white. This is helpful for getting rid of unwanted Grey areas in what should be the white part of the matte.
Holdout Group
The Holdout Composite takes the luminance matte of the foreground and pastes it as black (or other color) over the background. You can see the matte pasted onto the background with the View set to Holdout.
- Color: Sets the color of the Holdout matte through the use of a standard eyedropper or color picker. The default color is black.
Note: There may be times when you want to select a color from the background as the Holdout color. This will appear to give the foreground some atmosphere.
- Opacity: Sets the opacity of the color.
- Mix with Original: Blends the source and filtered images. Use this parameter to animate the effect from the unfiltered to the filtered image without adjusting other settings, or to reduce the effect of the filter by mixing it with the source image.
- GPU Rendering:Specifies how the effect is rendered.
- Default: Uses product-wide default of 16 bit half-float GPU rendering.
- 16 Bit Float: Manually force 16 bit half-float GPU rendering.
- 32 Bit Float: Manually force 32 bit full-float GPU rendering.
- Disabled: Forces CPU rendering.
