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PeterAUT
Participant
August 20, 2026
Question

Why does Object Mask not completely remove the background?

  • August 20, 2026
  • 2 replies
  • 32 views

We shot in front of a white sheet for a music video. Material is well lit and of good quality.

I apply the Object Mask to the Musician in front of the white sheet and it tracks him very nicely.

When I apply the Mask to opacity it does not fully remove the background. There is still a vague outline of the white sheet.

It is the only clip in the timeline so no influence from lower layers.

When I want to export the footage with Alpha the residue of the background becomes painfully obvious.

Thx for your help.

    2 replies

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    Community Expert
    PaulMurphyCommunity Expert
    Community Expert
    August 22, 2026

    Try this:

    1. Set Object Mask to Invert.
    2. Add the Alpha Adjust effect.
    3. Move the Object Mask assignment from Opacity to Alpha Adjust.
    4. In Alpha Adjust, set Invert Alpha.
    5. Add the Ultra Key effect.
    6. In Matte Cleanup, adjust Choke, Soften, Contrast, and Mid Point to remove the outline of the background.
    K
    Community Manager
    Kevin-MonahanCommunity Manager
    Community Manager
    August 21, 2026

    Hey ​@PeterAUT,

    Thanks for the post. Try Sharp Mask mode and use negative values in the Expansion parameter. Try a bit of feathering afterward. You can also shoot against a green screen and use Ultra Key as an alternative.

    I hope the community can also provide some pointers for you. Sorry for the frustration.


    Thanks,
    Kevin

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