Chroma key causes black background instead of transparency

When using the chroma key effect on an object, it produces a black background instead of transparency.  

For instance, trying to key out the green background of a greenscreen shot, it simply changes the green to black.  Even when the background color is set to white, the problem persists, and I am left with a big black rectangle with an actor inside.  What could be causing this?  Please help!


  • edited August 2016

    I've noticed that if you have a camera in the composite shot the keyed out area will appear black and not the checkerboard pattern that normally indicates a transparency.  Even though it appears black, it is still transparent.  Its important that the layer you want underneath the keyed out object is below it in the composite shot.  I would try bringing in a picture and placing the layer below the keyed shot and and see if it shows through the black.

  • The object underneath is below it in the composite shot, but same result.  I tried exporting it anyways, and it just shows up black, with some blue pixelations around the blood.

  •  That is strange.  Sorry I couldn't be of more help.  Hopefully one of the forum guru's chimes in.

  • Triem23Triem23 Moderator

    Can you upload the project?


  • edited August 2016

    Here is an example of my issue. It's just a short test.  This is using the action essentials pack, and as you can see, the black background of the squibs doesn't disappear. I added the muzzle flares and the blood mist by changing the blend mode of the layer, but I didn't want to do that for the blood burst because it didn't look as good.

  • edited August 2016

    Set the blend mode to screen or add

  • edited August 2016

    I want to avoid using that because I don't want the blood to be transparent.  

  • Put the Demult effect on the layer.

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