Create a cool TV bumper – using mattes in Adobe After Effects and this handy tutorial.

This tutorial will allow you to develop a deeper understanding about mattes, and how they can be used to apply texture and transparency to your layers in After Effects, by putting together a five-second television bumper in Adobe After Effects.

In this first part of a series of tutorials, you’ll learn how to take advantage of greyscale images – mattes – in After Effects. Starting with some basic images (and the AE project file included on this issue’s CD), we’re going to dirty up some clean computer type to give it a realistic feel.

You’ll use 3D space for positioning the image, and use the images and textures supplied to create the five-second effect shown at the end of the masterclass. Remember, the key is to have fun, and apply what you’re learning to your own projects.


01. A matte is completely independent of the alpha channel, but works in a very similar fashion. A matte is any greyscale image that is used to define transparency.

Each layer in After Effects can have its own matte. This can be done in several ways, but one way is to use a layer’s Track Matte setting. Create a new composition called ‘Scene 1’. Let’s start with the words “Coming Up” typed out with the AE Type Tool, as above.


02. Next, bring up the Modes column. If you cannot see the Modes column, right-click the column header, go to columns and select Modes. On the right side of the column, you see a TrkMat section. This allows any layer to use the layer immediately above in the stack order as a matte.

Currently it has no options, because there is not an image above the layer in the stacking order.


03 Place the image texture1.jpg just above the type layer. Now, under the Track Matte menu, four options will become visible.


04. As this image is a JPG, it cannot contain an alpha channel (embedded transparency). However, it does contain quite a bit of Luma (short for luminance) information, or greyscale imagery.

A ‘Luma matte’ disregards the pictures colour information and only looks at the greyscale information. The Track Matte function lets us use the texture of this image as a matte, therefore applying that greyscale information to the transparency of the text.

This is a great way to make ‘perfect’ computer type look more realistic. The other wonderful thing about track mattes is that they’re independent of the layer below.

Need a mask that doesn’t move with the layer? A track matte is a perfect solution. An important note – if the track matte layer does need to move with the layer below, it can simply be parented.


05. Now you need to set the matte filter. Let’s transfer imagery to the transparency of a layer. Refer to the image included with this tutorial, ink_matte1.jpg. This is a greyscale ink splatter image.

There is no transparency in the image, but, as we’ve learned, a greyscale image is just transparency in the waiting. We can easily apply this JPG to the transparency of another image.

This time, instead of a track matte, an effect called Set Matte will be used. Create a new black solid: Layer>New>Solid. Call it ‘Ink1’ and make it the size of the comp.


06. Next, you apply the effect. Click Effect> Channel>Set Matte. Add the file ink_matte1.jpg to the comp and turn off the visibility. In the Set Matte settings, find the Take Matte From Layer setting and select ink_matte1.jpg.

In the Use For Matte setting, set it to Luminance. Also, check the Invert Matte checkbox.


07. Essentially this image works the same way as a track matte. The luminance is used to define the transparency. This allows any layer in the comp to be used, and any part of the image: such as red, green, blue, channels, luminance, and saturation.

One thing to understand with this effect (and any effect in After Effects that references another layer like this) is that it only looks at the source of the layer.

In other words, when the layer ink_matte1.jpg is defined as a matte with Set Matte, none of the transformations, effects, and masks of that layer will be visible to the Set Matte filter, only the source image. However, the solid ‘Ink1’ can be moved wherever we want.


08. Repeat the above process for the image, ink_matte2.jpg, so you have this image.


09. You’re now ready to position the image in 3D space. Turn the type and the ink solid layer into 3D layers by checking the 3D switches for these layers in the switches column.


10. Switch to Custom View 1.


11 You’ll now see these 3D elements from a different perspective. Grab the Z handle of the type and drag it forward in Z space. With the Ink layers, grab the Z handles and push them backward in space.


12 Now you’re ready to try and create a second scene. Try constructing a “Next” animation, using the same elements and positioning, like the one above.


Tip 1

A ‘matte’ is any image that can be used to define the transparency of any given image – not to be confused with an alpha channel.

At any given time in After Effects, we can take a look at the alpha channel that defines the transparency for the entire visible image in our composition.

Black areas are transparent, white areas are opaque, and areas that are grey denote semi-transparency.

Next month

Part one of this TV bumper is sorted – in the next issue you’ll learn to create a camera move between this and another comp using the ‘collapsed transformation’ switch, as well as nulls and cameras.


Who: Harry Frank Harry stumbled into motion graphics as a starving musician. He lives in Detroit south of 8 Mile, earning a living as a designer, teacher, and rock star.

Contact: www.graymachine.com
Software: Adobe After Effects
Time to complete: One hour
On the CD: You can follow the tutorial yourself by using the files provided on this issue’s Digital Arts CD.