Introduction

This lesson was about Track Mattes and Luma Mattes in after effects.

Starter Task

The starter exercise was to re-create an animation shown on the tutor’s screen. This animation made use of the graph editor and the scale, position and opacity settings to practise and recap on skills we learned last year in After Effects.

Here is my finished animation:

Today I learned during this task that you can remove the easy-ease settings on a keyframe by Ctrl + Left Clicking that keyframe.

This task was useful for me to help get into the process of using After Effects again, and to help practice some skills that I learned last year.

What are Luma Mattes?

Luma Mattes work based on luminance – or the light/brightness in an image.

Luma Mattes are effects in After Effects that are created from black and white (greyscale) images. They can also be created from animations where the colour white is fully transparent.

Creating my own Luma Mattes

This task was to create a luma matte according to my tutor’s instructions. To do this, I started by importing an image into after effects and adding a text layer over the top.

Then, on the image layer, I enabled Toggle switches/modes and then from there I was able to select Luma Matte “HILLS” and that gave me this effect below, which I then animated using the scale co-ordinates:

As you can see, I had some of the scale graph editor settings left over from the previous composition of the yellow circles – but the main thing is that I learned a new technique.

Next, we practised inverted Luma Mattes following the tutor’s instructions.

I applied this inverted luma matte effect to two videos instead of two static images. I started by importing the ink video on top of the clouds video, and then selecting the luma matte option. this gave me the effect below:

However, this was not the inverted effect I was trying to create. To create that effect, I selected the Inverse Luma Mattes option in the same menu, and it gave me the following effect:

Here is the final product:

Practising luma mattes is useful for my own after effects work – I have a new skill to add to my experience.

Alpha Mattes

Here in this video, I have applied an alpha matte instead of a luma matte:

An alpha matte can be applied to a shape layer to reveal/conceal parts of the layer below. In the composition I made, I applied the matte to a rectangle layer that I placed above the white text. Moving the rectangle up and down revealed the text as the rectangle was moving, creating the effect of the text moving up from the ground.

Applying Luma and Alpha mattes to my own work

Here I created a short composition using the yellow dots composition I created at the start of the lesson. I changed their colour to white and made a Luma Mask on top of a video, and then I applied an Alpha Mask on some text over a video.

Conclusion

By the end of this lesson, I became comfortable using Alpha and Luma masks, as before today I hadn’t heard of them. These effects will be useful when editing videos in the future.