Busy/Blown Out Background Key Out

I have a clip with a talent standing in front of an off-white busy background with some blown out hotspots and I was able to use zMatte to mostly Key out the background so that I could replace the BG with a more even toned background and with hotspots toned down or removed. The zMatte did a pretty good job on remove the background, but I also used a Roto shape to get rid of the mask, and now the talent looks nicely isolated.

How can I apply another copy zMatte to help clean up the edges of the talent?

It seems like I’m not able to get the right IN/OUT on another zMatte, because it seems to still recognize the previous background, even though it “looks” like the BG has been cleaned out by the first zMatte and Roto.

Thanks for any help!!

Make sure you check out the zMatte tutorial on page 243 of the user guide. It is a fairly short read. You should be able to get a good key with one zMatte node if you use the Primary Matte, Secondary Matte as well as the Holdout and Garbage Matte inputs. Roto nodes can feed the Holdout Matte/Garbage Matte inputs.

  • A Holdout Matte defines foreground areas that should not be keyed out.
  • A Garbage Matte defines background areas that should be keyed out.

I’m making progress with the zMatte for keying the hotspots and filling in the area with my BG input, which I’ll fill with a grayish texture going in the final version.

In the mean time I was just testing out a Color Node (Green) going into the BG input temporarily, but I’m noticing that with the light wrap values turned up, I’m getting green wrapping within my Holdout matte, correctly, but I’m also getting green light wrap at the border of the entire 4096x2160 clip, which I don’t think is correct, or at least not what I intended.

Is there a way for me to remove the light wrapping on the clip border?


You probably have gray background values at the edges of the image. If so, use a Roto node plugged into the Garbage Matte input and place shapes on the edges of the image. This should help with the light wrapping on the edges of the screen.