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I've done about 1h of footage during a SCUBA dive with a Gopro Hero 2 (underwater housing, no filter), but the auto white balance algorithm messed up the colors and everything has a very strong green tint to it.

I understand that some light wavelengths get weaker with depth, hence the green tint, therefore I'd like to know how to fix this in post-production.

I have tried Adobe Premiere Elements 11, with the "smart fix" feature, and in some of the footage it seems to work fine. However, since the footage is quite dynamic, the algorithm gets confused and there's lots of flicker, as it constantly changes color corrections.

I have tried alternative programs that let me pick a "white" reference to correct the white balance of the video, but nothing on these clips is good enough to use to that effect.

Is there a way to determine the optimal color corrections for these clips, for example by picking them from a frame in the flickery "smart fixed" video that Premiere Elements outputs?

Any free applications that could help me here?

Samples below:

  1. http://goo.gl/CzQyZD
  2. http://goo.gl/CYlNYQ

EDIT: I've had some minor success with Adobe Premiere Elements 12 "auto color" mode, so it is possible to get something out of this footage. However, it flickers a lot since the color correction changes as the scene changes, even in the same clip. An example of 2 nearly-contiguous frames can be found in the comment below.

How can I force PE12 to use the same color correction across the entire clip, or at least figure out the proper color corrections from a given frame?

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Stills from auto-colored clip: goo.gl/9YyiQM (too green); goo.gl/hN7GhK (reddish, but acceptable). –  André Fernandes Apr 16 at 10:03

2 Answers 2

This is not the auto white balance screwing up. This is the way that SCUBA footage looks without artificial light. Even shooting with my SeaLife DC1400 which has specialized underwater white balance settings, you get a strong color cast, particularly in green water.

Water doesn't block frequencies of light evenly and as depth increases, much of the red light is lost from the spectrum. Unless you have an artificial light to put red back in to the color, there is no signal there to be had. The color cast comes from the color of the light exceeding the sensitivity of the sensor to be able to adjust for the imbalance between the red, green and blue light.

Update: Ok, I just looked at your footage and it looks like there may have been a technical glitch with it. That is extremely green, even for underwater footage. That almost looks more like a malfunction, but there still isn't enough information there to correct. It looks like red and even blue data is almost completely absent from the recording. I guess maybe my SeaLife DC1400 does a better job than I thought with color if there wasn't a technical problem there.

As far as ways to try and salvage it, you could go black and white with it or could try reducing the amount of green in it using a hue adjustment, but it still is only going to look "less bad" not "good". Wish I had better news for you, but it kind of goes with the territory of shooting underwater at any kind of depth at all without a light, particularly in colder green waters.

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Additional details: I've shot in the same conditions with a Canon IXUS 85IS and the results are much better, the tint in that case is blue but it's nowhere as saturated, and looks much closer to eye perception. This was an ocean dive, btw, so the water was "blue" with some green particles floating around. The gopro did well in the first 9m, then it went sour. –  André Fernandes Feb 5 at 22:19
    
Yeah, was going to say, I have vibrant colors with my Sealife down to about 30 feet or so and then it gets very blue tinted. It really does look rather extremely green though, even for underwater footage. I kind of wonder if the temperature may have made it start bugging out or something. Did it look ok again at the end when you were surfacing or did it stay that green? –  AJ Henderson Feb 5 at 23:16
    
The end of dive footage had normal colors, from ~5m up everything was fine. –  André Fernandes Feb 5 at 23:27
    
@AndréFernandes - hmm, odd. Does make me appreciate my DC1400 a bit more. –  AJ Henderson Feb 6 at 7:24

I had a look at it in After Effects (at first I thought that there wasn't any information at all on the red and blue channels, but there is). A few minutes' worth of mucking around with colour correction tells me that you're never going to get that to look normal. There is so little information in the red and blue channels that any attempt to balance the levels just brings up a ton of noise.

A workaround might be to colorize it to a reasonable colour, or go black and white.

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Did you get any acceptable (if noisy) results? I don't mind if it doesn't look perfect, could you share some RGB/hue/tint/saturation/etc. corrections for me to try? –  André Fernandes Feb 6 at 8:12

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