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Campfire flickering in post

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Davide Marchesi
Campfire flickering in post
on Jan 21, 2014 at 10:50:00 pm

Hello everyone, I was wondering if there's any effective way to add some of that classic campfire flickering to a few shots with a bonfire and little additional lighting. I know that probably the best way would've been to do it on location during the shooting, but I was by myself so that was not really an option.

Here's an example of the effect I like (even more subtle):







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Philip Bowser
Re: Campfire flickering in post
on Jan 21, 2014 at 11:37:49 pm

You can definitely achieve a look of flickering brightness with AE, but the shadows in your reference are also shifting in perspective because of the practical fire that was present. To manipulate the shadows in your footage would be incredibly challenging and time consuming to achieve with AE. But to just get the brightness flickering, I would probably use a combination of the Extract effect with a wiggle on an Exposure effect.

- Duplicate your footage in the timeline. Solo the above layer and apply the "Extract" effect. Bring up the "Black Point" until you've isolated only the brights of the image. Be sure to also bring up the "Black Softness" so there's a gradual fade into it.

- Then apply the "Exposure" effect, and use a wiggle expression on the Exposure property. Option/Alt click the stop watch next to the Exposure property and start by typing this into the expression field:

wiggle(5,0.5);


In this wiggle expression the first value (5) is the frequency, and the second value (0.5) is the amplitude. So this tells the Exposure property to randomly wiggle a maximum of 0.5 units 5 times every second. Play with those two values until you've got something you like.

You may want to apply this expression to the Gamma property instead the Exposure property.. depending on how dark your source footage is.

Hope this helps!

Philip. Bowser


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Dave LaRonde
Re: Campfire flickering in post
on Jan 21, 2014 at 11:45:40 pm

Even using a wiggle expression on the Exposure effect may not satisfactorily limit the effect to the parts of the subject you want. You may also have to create a matte to limit where the effect shows up... and if the subject moves a lot, it can get time-consuming.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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Philip Bowser
Re: Campfire flickering in post
on Jan 21, 2014 at 11:59:08 pm

Good point Dave! Didn't think of that.

Kind of reminds me of that old Video Copilot tutorial with simulating the muzzle flash lighting on the subjects face.

Philip. Bowser


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Dave LaRonde
Re: Campfire flickering in post
on Jan 22, 2014 at 12:12:48 am

Yeah, this effects stuff is a right royal pain in the worst body part you can imagine... missing the details can and will kill you.

But it's a lot of fun sometimes.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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Davide Marchesi
Re: Campfire flickering in post
on Jan 22, 2014 at 6:46:51 pm

Yeah, I thought that getting the shadows right could've been the main issue here. I'll give it a try and see if it's doable, otherwise I'll just do without. Thanks a lot to you both for the advice and Philip for the detailed explanation.


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