A short tutorial on creating Fire Birds
or MASKING TECHNIQUES
in AfterEffects

Requirements: Sufficient knowledge of PhotoShop and AfterEffects, understanding the principles of animation and different animation techniques. Timing.

We can use the layer immediately on top of any layer as a mask that only shows parts of the underlying layer. This can produce some interesting effects. In the example below we will make a fire bird, using a greyscale animation sequence as a mask and a real fire sequence.

Below you can see thumbnails of sample silhouette animation. The images are greyscale. The white pixels will be opaque and the black pixels will be transparent.

This is an image from our fire video:

1. Import the fire.avi and the masking sequence in AfterEffecs:

Be sure that the mask is imported as a sequence, so that it appears as a single layer in the timeline.

2. Position the two footages in Timeline mask on top, fire below it, like this:

The fire is instantly masked and looks now like this:

3. Give the fire a bit brighter look
Duplicate both the fire and the mask by pressing ctrl+D on the keyboard and then for the second instance choose Add as a blending method

This makes the brighter zones even brighter and gives a real fiery look

4. Final adjustments
You can apply any other effects that might make the animation look even more impressive.

What I finally did here is to Gaussian Blur the lower masking layer, so that it looks more less cut-out and give us this nice glow effect around the edges.

You can use the same method to create interesting effects in many situations - revealing the next scene, display titles, texturize waterfalls, psychedelic tunnels, etc.