LABINVERT

LAB / INVERT

Since the VOP's LIME compositing system is a strictly additive operation. By that I mean it can only make the latent image pixels brighter with the incoming exposure. Because of that, it at first may seem impossible to make the latent image darker. Now, why would you want to make pixels darker if you usually start with black background and only light up the pixels that doesn't need to be black?

Enter, the LAB / INVERT button. By pressing it. You send the content of the camera mag "to the lab" so to speak. And what you get back is the inverted color version of those images. When you do this, you now are in the position where black is white. Where you can use brightness to burn in darkness into the latent images. And once done, you hit the same LAB / INVERT button again to send it back to the lab so that you get the original colors back but now the added bright pixels have turned dark.

For a hands on example of how to use this in a real shot, see the tutorial for Holdout Mattes.