Universe

Alpha Channels and Resolve

With Blackmagic's DaVinci Resolve, you'll need to follow a specific workflow when working with Universe text effects (or any effects that use alpha channels). For the purpose of this guide, you'll need to know the basics of Resolve, keying, and that an alpha channel is essentially transparency information, separate from RGB channels.

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Step by Step

To start, you'll need your Resolve text video layer above your footage's video layer, positioned within the frame where you'd like it to be.

• Convert your text into a compound clip.
• Bring that newly-created compound clip into Resolve's Color tab.
• Decouple the first node from the output.
• Add a new Corrector node.
• Feed the Corrector node the alpha and RGB inputs from the first node.
• Apply your desired text effect onto the first node.
  • For a Universe text effect, make sure to toggle its "Unmult" option within the Effect Controls.
• Option A: Keying the Effect
  This is best suited for text effects that have solid outputs, like Long Shadow or Luster. Avoid using this with effects that have gradients, such as Glo Fi II or Holomatrix. Otherwise, you'll have large dark areas around where the gradient meets what should be a transparent background.
  • Key out the text from its background in the Corrector Node.
    1. Select the Corrector Node.
    2. Select the eye-dropper section.
    3. Pick the eye-dropper tool.
    4. Select the text.
    5. Flip the key.
    6. Head into the Keyer section and adjust the Key Input so that everything but your text and its effect are stenciled out.
• Option B: Unmult the Effect
  Use this for effects that have gradient outputs over what should be a transparent background. Note that this method can result in some additional, unwanted transparency within the effect, which is unfortunately a byproduct of how alpha channels are created and output through the host.
  • Add Universe Unmult to the Corrector Node.
    1. Select the Corrector Node.
    2. Add Universe Unmult to the Corrector node.
• Add an alpha output node.
• Feed the Corrector node to the RGB and alpha output nodes.
• Right-click in the Node interface and select Use OFX Alpha.

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Comparison

Since Unmult turns everything black and near-black transparent, this can mean darker colors show some transparency when used on a solid effect.

On the other hand, since keying strictly turns only black (or whatever color you've selected) transparent, it can output less than optimal results.