Keying with Polar Fringe

Hello video wizards.

I have this image:

And I’m patching it like this:

Visual Cortex Input Encoder > RGB into Polar Fringe > THRU into RGB CH.A of Marble Index
Key Neg. of Polar Fringe> Opacity VC of CH.A of Marble Index
RGB OUT of Marble Index into RGB CH.B of Visual Cortex.
Output Encoder

For what I understand and what i’ve read it’s the basic patch for substracting a color from RGB.

I have all controls of Polar Fringe like in the Reference Card. MI switches are all centered and Visual Cortex is being used just for the output encoder.

My problem is that when moving the joystick of Polar Fringe It doesn’t substract any color. The image stays the same besides some subtle changes on the overall opacity. It doesn’t matter if I use the Negative or Positive Key.

I don’t know if I’m doing something wrong or not understanding the module correctly. Cause it seems pretty straigthforward.

I hope someone can help me :robot: Thanks!


try sending visual cortex encoder rgb outs into polar fringe and the thru out from polar fringe into a channel of the visual cortex and the negative key from polar fringe to the composite input of the visual cortex

see if you can make progress with that setup first

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Can you show us a pic of your settings on both modules? Make sure you have the Opacity control fully CCW and opacity CV level fully CW.


You also might try a source with more color, unless you’re specifically targeting the purple stripes. In any case, a more colorful source may help you get a handle on the patch better.


Thanks folks, it works now :slight_smile: I guess I had the CV pot on the middle.