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Color Stabilizer
I am trying to deal with some table-top footage of mechanical toys, shot with a high-speed video camera against a seamless background. The light levels fluctuate, due to the extremely high frame rates.
I have been trying to use Color Stabilizer on AE 7 to even out the levels, and the results are not great. I would appreciate hearing from someone who can give me some insights as to how this filter actually works. Since nothing I have tried makes that much of a difference, I’d like to get some guidance.
Depending on the method chosen, you are supposed to position the “black,” “midpoint,” and “white” markers at the appropriate spots on your comp. What is the purpose of these markers? Should they be placed on areas that DO change or areas that DON’T? I have tried positioning the black on a pure black, white on a pure white — but I have also tried putting the black on a dark area which fluctuates more than the pure black, and the white on a light area which fluctuates more than a pure white area.
I have also tried applying the Color Stabilizer several times, stacked up. It seems to be helpful with two applications, and to get worse with three.
Thanks very much.
— Bob C
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2 Replies
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Hi Bob.
Let me first apologize for being in a hurry and not doing my usual thorough checking before I answer.
That said, maybe I can get you there. It’s been a while since I used this plugin, but I used it a couple of times, and found the results to be pretty amazing. The interface for the plugin is, as you have suggested, puzzling, though.
There are global fluctuations of luminance in an image and local fluctuations. The plugin is meant to correct the former. If there are too many local fluctuations (the UFO in the example below), you probably will have a real tough time.Let’s see if memory serves.
Try using the levels option first: in order of complexity, brightness is the simplest, then levels, then curves (which, as I recall, was just too complicated to work for my application).
You need to place the black and white marks where the image is darkest and lightest, respectively, but fluctuations of values in these areas should be correctable, that is, global fluctuations. For example, let’s say you have a bright sky and you put the white sampler mark in the sky. That’s fine, but if a bird or cloud or UFO flies behind that sample mark, the plugin will try to compensate by changing the levels globally. You can see why this will yield bad results. To stick with this example, if I really want the mark to sample those bright sky areas, I’d have to animate (keyframe) the white point sample mark for those UFO frames, moving it to get out of the way of the UFO so that it samples the bright sky only.
Also, use a big sample size. This, if I remember correctly, was pretty important. I think I used sample sizes of at least 10 pixels, probably more like thirty. Of course, this depends on the image. The default sample size is 3, which was always way too specific.Good luck …
CG
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Thanks CG for the explanation. I tried resetting the sample size. I’m even making a comp from the first comp, and stabilizing that one. The results are still poor.
Perhaps the reason I’m not happy is that this is table-top work on a “sweep” of gray paper, with a gradual fall-off of light away from the subject. The change in luminance values results in the gray-to-white “ramp” moving to and from the center of the image. I don’t think the fluctuations on the subject itself are noticeable. So I’m doing a lot of masking.
When I try the third option, Levels, with three locations for black/midpoint/white, the result becomes crazily erratic, with Color Stabilizer actually destabilizing the values dramatically.
Thanks again.
— Bob C
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