fan/flicker/strobe effect at DVinfo.net

Joe Riggs · June 12th, 2009, 01:41 AM

We shot a scene where we placed a light above a fan, and that created a cool flicker/strobe effect. Unfortunately, there was a couple of shots where we forgot to turn the fan on and therefore they lack that effect.

Any suggestions on how to achieve that flicker/strobe effect in post?

Gregory Gesch · June 23rd, 2009, 06:30 PM

Hi Joe. Is it possible to get a look at a bit of footage where the fan is operating to be able to see exactly the effect you have already? Do you use After effects?

Jon Jaschob · July 5th, 2009, 01:53 PM

If your using AE,
Maybe placing an adjustment layer above your footage, and adding levels.
Adjust the levels to the brightest flash you want.
On the adjustment layers opacity use the wiggle expression. wiggle(2,50) [example]
If you need to isolate the flashing use a mask on the AL.
You can also hook up sliders to the two wiggle parameters so they can be keyframed.
Jon

Ray Bell · July 9th, 2009, 05:40 AM

Joe... OK I think this should work out for you...

Just get a fan, a light source pointed at a white wall and get the fan into the light
path and adjust the speed of the fan for matching your other footage....

now with your camera shoot the wall and get the strobe effect onto the camera...

now in post you just put the strobed footage on top of the footage you want to have
strobed... now you can set the layer to overlay and adjust the opacity of the strobe
footage until the output matches...

June 12th, 2009, 01:41 AM	#1
Joe Riggs Regular Crew Join Date: Dec 2005 Posts: 189	fan/flicker/strobe effect We shot a scene where we placed a light above a fan, and that created a cool flicker/strobe effect. Unfortunately, there was a couple of shots where we forgot to turn the fan on and therefore they lack that effect. Any suggestions on how to achieve that flicker/strobe effect in post?

June 23rd, 2009, 06:30 PM	#2
Gregory Gesch Regular Crew Join Date: Jun 2009 Location: Brisbane Australia Posts: 114	Effect Hi Joe. Is it possible to get a look at a bit of footage where the fan is operating to be able to see exactly the effect you have already? Do you use After effects?

July 5th, 2009, 01:53 PM	#3
Jon Jaschob Major Player Join Date: Oct 2005 Posts: 232	If your using AE, Maybe placing an adjustment layer above your footage, and adding levels. Adjust the levels to the brightest flash you want. On the adjustment layers opacity use the wiggle expression. wiggle(2,50) [example] If you need to isolate the flashing use a mask on the AL. You can also hook up sliders to the two wiggle parameters so they can be keyframed. Jon

July 9th, 2009, 05:40 AM	#4
Ray Bell Regular Crew Join Date: Nov 2004 Posts: 1,414	Joe... OK I think this should work out for you... Just get a fan, a light source pointed at a white wall and get the fan into the light path and adjust the speed of the fan for matching your other footage.... now with your camera shoot the wall and get the strobe effect onto the camera... now in post you just put the strobed footage on top of the footage you want to have strobed... now you can set the layer to overlay and adjust the opacity of the strobe footage until the output matches...