Now, to clean up the composite, let’s look at the primary matte directly. Set View to Primary Matte, and adjust Background>Position until the backing color area is solid black. Now, adjust Foreground>Range until the foreground area is solid white. Try to get a clean edge without using Shrink/Grow at this stage; matte choking should be a last step when other adjustments haven’t cleaned up the edge. Experiment with the blur settings to get an edge that doesn’t look too hard, but isn’t too soft either.
Stop! You should stop now and take note that the background matte painting looks substantially sharper than the DV foreground footage. You should add a blur effect to the background to make it match the apparent sharpness of the foreground. I tried Fast Blur set to 1 pixel, both horizontal and vertical. You may find another filter more effective. However, if you do not match the background to the foreground the final composite will never look right!
Open the Edge control section. The Edge Matte is set by default to add a 1-pixel clean edge; at this point, this may look fine or it may be a dark line or a greenish edge to the subjects. Change the Opacity control (which works backwards from other programs) to 100% to make the edge transparent. You may later come back and make it partially opaque and slightly blurred; you can also color correct it to remove any residual green or make it match other effects.
Before we move on to try the Light Wrap feature, let’s stop and add our garbage matte. Right-click on the footage in the comp window and select Mask>New Mask. Now right-click again and select Mask>Free Transform Points. Drag the right side of the mask in to cut out the junk on the edge. This is a garbage matte at its simplest; of course, you can make masks any shape, feather the edges, and do all sorts of other things if needed. In this case, a simple crop is all that is required. In just a moment, we’ll create a more complex mask.
Now, in the zMatte Effects Control panel, open the Light Wrap control. In the dropdown Background menu, select cityruins.jpg. This is to tell the software that it is this layer that the light will appear to be coming from.
Light controls the intensity of the effect; Wrap controls the width of the intrusion of the effect into the foreground. Experiment with both until you find a setting that looks realistic. I was happy with Light 190 and Wrap 25.
If you have a dark edge at this stage, it is probably coming from the Edge Matte. Turn the Opacity down (up) to 100%, thus making it transparent. Go figure.
