Layers are the elements that make up a composition. Without layers, a composition is only an empty frame. Use as many layers as necessary to create your composition. Some compositions contain thousands of layers, whereas some compositions contain only one layer.

Layers in After Effects are similar to tracks in Adobe Premiere Pro. The primary difference is that each After Effects layer can have no more than one footage item as its source, whereas a Premiere Pro track typically contains multiple clips. Layers in After Effects are also very similar to layers in Photoshop, though the interface for working with layers differs.

Four layers as viewed in the Composition panel (top) and in the Timeline panel (bottom)

You can create several kinds of layers:

• Video and audio layers that are based on footage items that you import, such as still images, movies, and audio tracks

• Layers that you create within After Effects to perform special functions, such as cameras, lights, adjustment layers, and null objects

• Solid-color layers that are based on solid-color footage items that you create within After Effects

• Synthetic layers that hold visual elements that you create within After Effects, such as shape layers and text layers

• Precomposition layers, which use compositions as their source footage items

To see a video tutorial on creating and managing layers, visit the Adobe website at www.adobe.com/go/vid0222.

When you make a change to a layer, you do not affect its source footage item. This means that you can use the same footage item as the source for more than one layer, and use the footage differently in each instance. (See Importing and interpreting footage items.)

Changes made to one layer do not affect other layers, unless you specifically link the layers. For example, you can move, rotate, and draw masks for one layer without disturbing any other layers in the composition.

After Effects automatically numbers all layers in a composition. By default, these numbers are visible in the Timeline panel next to the layer name. The number corresponds to the position of that layer in the stacking order. When the stacking order changes, After Effects changes all numbers accordingly. The layer stacking order affects rendering order, and therefore affects how the composition appears for previews and final rendered output. (See Render order and collapsing transformations.)

After you add a layer, you can reposition it in the Composition panel. In the Timeline panel, you can change a layer’s duration, starting time, and place in the layer stacking order.