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Hello, I have a QuickTime of some black and white animation a friend did in a different program and I'd like to do drawovers . Problem is I can't use the light table because it's registering the white bg as strokes. Since this is all black line work on a white bg, is there a way to remove all white in that layer and just leave anything black so I can see it when using the light table? thanks!

Scan Cleaner.

And the scan cleaner effect can be found in the FX stack under Add FX /Color.
Also, if you want to keep the opaque white for what reason ever, you can lower the layer density and change the light table mode from "colour" or "gradient" to "none". This can be useful if your drawings are made of lines of different colours and you want to keep it that way, because the scan cleaner turns everything to grays, black and white (I think in the latest version there's also a color preserving scan cleaner, though).

Also try turning off the colors in your Light Table by switching them to image color.

EDIT: 2bert beat me to it. I'm using a different name because I'm working with a different version od TVPaint. For this reason in the future it is a good idea to give the version (all decimal points) of your TVP and your operating system.