BCC Make Alpha Key

Category: BCC Key and Blend

Effect Name: BCC Make Alpha Key

The BCC Make Alpha Key filter, part of the BCC Key and Blend category, creates a new alpha channel from one of the existing channels in the image and then applies levels and gamma correction to the new alpha channel.

Working with the Filter

Presets and Common Controls

• BCC filters come with a library of factory installed presets plus the ability to create your own custom presets and preview them with the BCC FX Browser™.
• BCC filters also include common controls that configure global effect preferences and other host-specific effect settings.

For more information about working with presets and other common controls, Click Here.

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.

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.

• Alpha Source Layer: Selects the clip or layer to be used as the source layer. If you choose None, the filtered layer is automatically used as the source.
• Alpha From Channel: Selects the channel used to create the output alpha channel.
• Luminance
• Red
• Green
• Blue
• Alpha
• Full On
• Full Off
• Luma Inverse
• Red Inverse
• Green Inverse
• Blue Inverse
• Luma Folded
• Red Folded
• Green Folded
• Blue Folded
• Output: Determines how the output of the filter is rendered.
• Composite: Uses the new alpha channel, making portions of the image partially or completely transparent when composited over the new background.
• Composite Inv Alpha: Inverts the new alpha channel.
• Show Matte: Displays the matte instead of the composite.
• Show Invert Matte: Displays the inverted matte.
• Mask Transparent Pixels: Displays the source image with a red mask over the transparent pixels.
• Input Black: Determines which values in the alpha channel are treated as purely transparent. All pixels more transparent than the Input Black level map to the Output Black transparency level.
• Input White: Determines which values in the alpha channel are treated as purely opaque. All pixels more opaque than the Input White level map to the Output White transparency level.
• Gamma: Controls the slope of the curve used to convert from the input color values to output values in pixels brighter than Input Black and darker than Input White. Increasing Gamma from the default of 100 lightens the image and decreases contrast, while decreasing Gamma darkens the image and increases contrast.
• Output Black: Sets the minimum opacity of the image. Increasing Output Black lightens the black areas of the matte, increasing their opacity.
• Output White: Sets the maximum opacity of the channel. Decreasing Output White darkens the white areas of the matte, decreasing their opacity.
• Post Blur: Applies a blur to the alpha channel after the key is created. Use Post Blur to soften the edges of the matte for sources with high-contrast edges.
• Alpha Offset: Controls an offset that is added to the output alpha. You can create a transition by animating this from –255 to 255. At a value of -255, the entire image keys out. At a value of 255, the entire image is opaque.
• Choke: Adjusts the size of the opaque portion of the matte. Positive values expand the opaque areas, while negative values contract them.