Motion Science Demonstrates Using Shift Channels for a Better Composite Smoke and Fog Effects
It’s easy enough to knock out the black when working with smoke and fog stock VFX clips by using a “Screen” blend mode. Is that the best way though? Screen-mode does shift the brightness of your plate by quite a bit. Cameron Pierron of Motion Science fame shows another method that might work better for you: Using Shift Channels.
In After Effects the Shift Channel effect allows you to replace a clip’s channel with another. You can tell the effect to use “something” as the red, blue or green channels, rather than the original clips red, blue or green. You can also tell the effect to use the luminance of the clip as an alpha channel.
Using the luminance of smoke or fog effect is a great way to get rid of the black in the stock shot. So the next time you need to composite smoke and fog effects and have it look real, take Cameron Pierron’s quick tip and try the Shift Channels effects instead of the Screen transfer mode.