Video Explainer (04_AAEFR_24)

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Welcome to you.
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In this explainer, I’ll add a simple expression to the video to make it flicker ominously, then animate a light flare from left to right as it becomes brighter.
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This video is part of a series but can be viewed on its own.
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Expressions in after effects are short scripts that adjust a single layer property over time.
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For example, I could create hundreds of keyframes to vary the brightness of my video clip over time and try to make it flicker realistically, but this could take me hours.
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Here’s how I can do it using a simple expression.
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I’ll start by adding the brightness and contrast effect to my video clip layer.
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Expand this effect to view the separate options for brightness and contrast.
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As you’d expect, varying the brightness will do something like this, and varying the contrast will do this.
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I’ll make sure the playhead is at the start of my clip.
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Hold down the alt key on the keyboard and click on the stopwatch next to the brightness property.
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Holding down the alt key when I clicked tells After Effects I want to enter an expression for the selected property.
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I’ll type in wiggle, that’s w i g g l e, open bracket, 10, comma, 100, close bracket, then play the sequence.
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This simple expression is adjusting the brightness 10 times a second, the first number in the brackets, by up to 100 from its original setting, the second number in the brackets.
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This first number is the frequency and the second number is the amplitude.
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I can play around with these values until I’m happy with the results.
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I’ll do the same for the contrast property.
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As your knowledge grows, you’ll discover expressions can be used in all kinds of time saving ways.
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For links to useful resources, see the website.
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Next, I’m going to add a flare that’s going to travel from left to right across the video as it increases in intensity until the video clip is completely bleached out to bright white.
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Start by searching the effects and presets panel for flare.
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I’ll drag the lens flare effect onto the video clip layer.
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Even with the flares default settings, I can see an immediate change to the appearance of the video through the text.
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I’d like the flare to move from approximately here to over here while getting brighter all the time.
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As before, make sure the playhead is at the start of the animation sequence.
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Expand the properties of the video clip layer.
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Here are the properties for the lens flare.
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I’ll place the flare center roughly where I want it.
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Click on the stopwatch and place my first keyframe.
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Move the playhead to shortly after 6 seconds when the zoom animation finishes and move the flare across towards the top right of the text.
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I’d like the flare to start off a bit brighter than it currently does, so I’ll switch on the key frames for this property.
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Select the first key frame and increase the flare’s brightness.
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Move to the end key frame and increase the flare brightness until it very nearly makes the entire text bright white.
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It’s certainly getting there.
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I’ll carry on adjusting the properties for the flare.
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In the final explainer in this series, I’ll export the composition to an MP 4 video and look at some great online resources you can use to continue your after effects journey.