Using Track Mattes in After Effects

Track Mattes are a powerful tool for controlling the visibility of one layer based on the transparency of another, allowing you to create interesting reveals, masks, and effects. They’re one of a few reveal techniques inside Adobe After Effects. Let’s take a look!

Track mattes are a powerful way to control what parts of a layer are visible. They work by using one layer to “cut out” or reveal another. In recent versions of After Effects, track mattes are more flexible and easier to manage than ever.

What Is a Track Matte?

A track matte uses another layer’s shape, transparency, or brightness to determine what shows on a target layer. You might use a shape layer to reveal text, or a gradient to fade something in.

As of After Effects 23.0, you no longer need to stack the matte directly above the layer it affects. You can choose any layer as the matte using a dropdown or pick whip.

The Track Matte Column 

When you enable the Track Matte column in the timeline using the Transfer Controls pane, you’ll see:

• A dropdown menu to select any layer in the comp as the matte

• A mode toggle for switching between Alpha and Luma

• An invert button to flip the matte result

This makes it much easier to manage your mattes, especially in comps with many layers.

How to Use a Track Matte

Here’s how to set one up:

1. Create the layer you want to use as the matte (like a shape, text, or gradient). Think of this as the boundary limiting visibility.
2. Select the layer you want to be affected (your target layer).
3. In that layer’s Track Matte column, use the pick whip or dropdown to assign the matte layer.
4. By default, it will use the Alpha (transparency) of the layer matte. You can use the adjacent button to swap to Luma (brightness).
5. Click the Invert button if you want to reverse the visibility outside the visible space of the matte layer.

Your matte layer doesn’t need to be directly above anymore. And if you reuse it for multiple layers, it stays where it is.

Alpha vs. Luma

• Alpha Matte: Uses the transparency of the matte layer. Wherever the matte is visible, the target layer shows through.

• Luma Matte: Uses brightness values instead of transparency. White areas reveal the layer; black areas hide it.

Use Alpha for shapes, text, or logos. Use Luma when working with gradients, video, or black-and-white images.

Inverted Mattes

The Invert button gives you the opposite result of your matte:

• Alpha Inverted: The target layer shows everywhere the matte is not visible.

• Luma Inverted: The target layer shows in darker matte areas and hides in lighter ones.

This toggle gives you more control without needing separate matte layers.

Example: Text Reveal with Shape Matte

1. Create your text layer.
2. Create a shape layer that you’ll use as the matte.
3. Animate the shape so it slides across the text.
4. Select the text layer.
5. In the Track Matte dropdown, choose the shape layer.
6. Make sure Alpha is selected.

The text will appear only where the shape overlaps it, creating a clean, animated reveal.

Matte Layer Visibility

Once a layer is used as a matte, it becomes invisible by default. If you need to see or animate it, toggle on the visibility in the timeline panel.

Tips for Working with Track Mattes

• You can reuse a single matte on multiple layers.

• You can animate the matte for dynamic reveals.

• Keep matte layers named clearly so they’re easy to find in the dropdown.

• If your matte layer has effects, those will influence the result—use this creatively.

Wrap-Up

Whether you’re revealing text, masking out part of a video, or creating a transition, track mattes let you control visibility with precision.

In the next lesson, we’ll look at masks, another way to hide or reveal content, but with a more hands-on, shape-based approach.