UCanCallMeAl

Q: Light Flicker/Strobe Problem; similiar to TV

Hello All,

 

Customer had a sword in a lighted display case and the light cycles through various colors. The lighting is causing a flicker similar to what you see when someone films a TV screen.

 

Shot in 1920 and some 4K to.

 

Any advice?

 

Thanks.

Al

iMac, OS X Yosemite (10.10.3)

Posted on Jun 2, 2016 8:20 AM

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Q: Light Flicker/Strobe Problem; similiar to TV

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  • by David Bogie Chq-1,

    David Bogie Chq-1 David Bogie Chq-1 Jun 2, 2016 11:36 AM in response to UCanCallMeAl
    Level 7 (25,772 points)
    Video
    Jun 2, 2016 11:36 AM in response to UCanCallMeAl

    It's a tough situation. Your shutter speed was out of sync with the lighting instrument, probably fluorescent or sodium, that was operating at mains frequency. Solutions depend on the use of the footage. If you bring the clip into its own project, reduce its speed dramatically, you can apply a good set of color correction controls that change on adjacent frames. Share that out as a master, bring it back into the same project as an upper or lower layer, and try various blend modes to see if the problem can be smoothed out by averaging the pixels. If you have zooms or other movements this process might not be satisfactory. The beauty of key framing the color correction changes is your lighting changes in a predictable patter as the shutter moves in and out of phase with the lighting. Once you have a good set of keyframes you can copy and paste them easily if you're using Motion.

     

    Say, how are your Motion chops? You can grab a still image and matte it into the shot. Your ability to hide the matte depends on your skills and if the shot moves.

     

    Do you know an After Effects artist? There are filters in AE like Stabilize Color and Leave Color that can actually perform pixel-based miracles.

     

    Others will have additional, likely better suggestions. Best of luck.

  • by UCanCallMeAl,

    UCanCallMeAl UCanCallMeAl Jun 2, 2016 11:39 AM in response to David Bogie Chq-1
    Level 1 (18 points)
    Mac OS X
    Jun 2, 2016 11:39 AM in response to David Bogie Chq-1

    Ok that gives me a start.

    Not sure about "adjacent frames."

     

    I do know enough Motion to do that.


    Fortunately I took enough still shots that I'm ok but would love to use that video as well.

     

    Thanks for the input.

    Al

  • by David Bogie Chq-1,

    David Bogie Chq-1 David Bogie Chq-1 Jun 2, 2016 3:14 PM in response to UCanCallMeAl
    Level 7 (25,772 points)
    Video
    Jun 2, 2016 3:14 PM in response to UCanCallMeAl

    UCanCallMeAl wrote:

    Not sure about "adjacent frames."

    Thanks for the input.

    Al

    Hope you get it sorted out.

    these kinds of exposure errors create subtle changes on adjacent frames. You can set keyframes one frame apart if necessary but it's tedious. You want to be able to average out the changes by showing to boost the lows to meet the highs or reduce the highs to meet the lows. But if you try to adjust both high and low exposures to meet in the middle you're going to be creating twice as many keyframes.