Compositing and transparency overview and resources

Learn how to composite transparent layers in Adobe After Effects using alpha channels, blending modes, and mattes for precise results.

To create a composite from multiple images, you can make parts of one or more of the images transparent so that other images can show through. You can make portions of a layer transparent using any of several features in After Effects, including the following:

• Roto Brush and Refine Edge tools in CC 

• Masks and Rotoscoping 

• Mattes 

• Painting on the alpha channel 

• The Preserve Underlying Transparency layer option 

• Keying effects 

To make an entire layer uniformly transparent or semi-transparent, modify its Opacity property.

Layers can also be composited together without modifying the transparency of the layers themselves. For example, you can use blending modes or some of the Channel effects to blend image data from multiple layers into a composite. 

After Effects also includes the mocha shape for After Effects (mocha shape AE) plug-in, which converts paths from mocha-AE into mattes in After Effects. 

Adobe Photoshop is an excellent application for performing many compositing tasks, including defining areas of transparency using its selection and painting tools. You can use Adobe Photoshop together with After Effects for optimum efficiency and best results when doing compositing work.