Q: Hi. Does anyone know how I can balance the light in a clip that changes from light to dark and back to light again again?

Split the clip and put a longish cross dissolve between the sections.

1: Are you just trying to cure one problem? Tom's suggestion might work.

2. Is your whole clip affected, does the lighting go up and down in a rhythm? 

3. Were you shooting under fluorescent lights?

If you are referring to changes in the exposure of the video clip over time and wish to even out that exposure, I have found the best solution to this in FCP X is to use keyframes in the Color Finale plugin to adjust the exposure appropriately. By judicious use of keyframes you can smoothly change the exposure as needed in the clip.  I suggest Color Finale because it allows key framing whereas the color correction effect in FCP X does not.

Tom

sineke wrote:

 

1: Are you just trying to cure one problem? Tom's suggestion might work.

    It's one clip.

2. Is your whole clip affected, does the lighting go up and down in a rhythm?

    The light goes up and down in an uneven rhythm

3. Were you shooting under fluorescent lights?

    I was shooting under daylight bulbs.

 

Thanks

The only ways an exposure can change up and down repeatedly are if the f-stop is shifting (something in the frame is causing this), you've set your camera to auto adjust the shutter speed instead of the f-stop, or your lighting system is strobing on and off (using the mains frequency) at a rate that creates a harmonic with your shutter speed. That harmonic is periodic and regular, it will not vary. If your mains is 60Hz and you're shooting at 1/48 second, you only catch the maximum brightness of the fluorescent or high pressure sodium vapor lighting instruments for a few seconds during periodic sine waves. 

"Daylight bulbs" could be anything and doesn't really explain your lighting source but, okay.

Color Finale is one of several enhancement filters available for FCPX. Very powerful and they offer a fully functional 7 day free trial.

I use CineFalre White Balancer,far less expensive but not anywhere near the complexity or flexibility. CineFlare runs inside FxFactory.

Totally keyframable.

You've gotten lots of good advice on this.

Just to say that another way (which FWIW is one I like) is to duplicate the problem clip and stack the copy directly on top of the problem clip. Set the exposure in the top clip to whatever value you need to compensate for the peak fluctuation and then key frame the opacity.

Russ