After Effects On the Spot[c] Time-Saving Tips and Shortcuts from the Pros

When Two Alphas Don't Add Up

When compositing two or more objects that have their own alpha channels, you sometimes get a dirty edge. This problem is more visible when the objects have soft edges or are being animated. The solution? Composite layers normally, but be sure to set the top layer(s) to the Alpha Add blending mode. This mode goes a long way in achieving visibly better edges when combining alpha channels.