Problems with watertank effects and ink drops.

[Kirk Smith]

I’m just throwing this in there, so don’t think I really know what I’m talking about in any way.

What I would try is putting a green or blue plastic sheet on the back side of the fish tank (is it a square one of round?) and then putting the camera right up the the glass. Make sure you’re properly focused where you need to be and try that. As long as the water is clean there should be no refraction or anything since you’re filming straight on.

Is the camera you’re using a waterproofed one? If so then sticking it in the water might help, too.

Like I said, I don’t really know what I’m talking about, this is just where I would start.

[Kevin Camp]

i’m not sure how you’re set up, but i would shoot black ink on a white background, then generate a matte from that rather than ‘key’ the ink.

a big advantage of this is you can work with just the luminance values of the clip and avoid the lower quality, more highly compressed components of the video signal. applying the tint effect will effectively extract just the luminance from the footage which is the cleanest channel to work with. then it’s just a matter of adjusting levels/curves and some rotoscoping to clean up any debris/lighting issues…

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW

[Michael Szalapski]

Kevin is very, very right. Black ink on a white background is a much better way to go. You can use black and white shots as a track matte in your NLE without even going into After Effects at all.

The wiggling you are describing is due to the compression of dv footage. It’s got noise in it; that’s the nature of shooting without a great camera.

What specific problems are you having with your tank shots?

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[David Bogie]

There was a recent post on one of AE Tutorial sites about the effects wonks who shot Close Encounters of the Third Kind. Complete exposé about their tank effects. They used cold salt water floating on top of hot fresh water and then injected white latex paint (in various dilutions) between the two layers of water.
It was much more complicated than that.

I’ve shot lots of tank stuff but just with inks against white and white latex against black with various colored lights. It’s all about experimentation and lots of cleaning up. Never got into using fluids with different densities.

bogiesan

[Kai Indvik]

thanks for all of the answers!
I eventually wound up using white in on a black background, in a darkroom. This fixed the problem of reflections I was having. Thanks again for the answers.

Golf is a good walk spoiled
~Mark Twain