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Removing ‘smoke’ from a soft bg shot
Hi,
I’ve got to do a composite on a shot that meant to look like a summer street party, but it was shot on a cold winters morning. We have some nice sun in shot, so that’s ok, but the actor’s breath is condensing as they breath. It ruins the feel a little.So I want to remove the puffs of smoke that they breath.
The background focus is quite soft and you only really see the breath on the background because of our shot selection.
I am wondering if I should use color correction techniques to remove the breath that is slightly higher in luminance (but there’s a good variety of light and dark in the bg too).
Or should I track another bit of appropriate bg (no breath) on to the trouble areas. Tried this, but because the bg is soft, it is difficult to get a really accurate track!
Or is a another way to approach this?
Many thanks for your suggestions
Rob
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3 Replies
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Removing the smoke will still mean that you have to replace the background. So, your options are either to roto (clone brush) or track (and replace with appropriate footage + color & mood match).
Without looking at the shot, it’s impossible to say which way you should go in order to find the best solution.
Good Luck!
RoRKbroadcastGEMs.com – the leader in customizable royalty-free animated backdrops
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Great tip, thanks, will give the cloning a try.
Cheers,
Rob -
Well, this could be a major pain, but I’ve seen a technique for removing things like rain from shots by averaging several frames of footage together. Basically duplicating some number of layers of your footage, offsetting them each by a frame or two then lowering the opacities of the upper layers (keep the bottom layer at 100%). There’s most likely a mathematical way to figure out what opacity values are necessary for each layer to contribute the same amount to the overall image, but I can’t test any ideas right now (no AE on this computer).
The above technique would only work on a locked down or stabilized shot.
Since the breath is lighter than the background, you could also try a larger offset (a couple of frames) and setting the upper layers to the ‘Darken’ blend mode. This might be more effective, but the shot still needs to be locked down or stabilized.
Either of those techniques would also require that you have fresh copy of your original footage with the foreground loosely matted above the background that you’ve created, otherwise you might start to see several frames of your actors in different positions.
Darby Edelen
NVIDIA
Santa Clara, CA
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