Get alpha mask from chroma key

Hi!

This is my 1st time using Natron. I need to get the alpha mask from a chroma key, and I’m stuck in something that should be very simple: I’m keying and applying a roto but outside the roto the pixels are white, and I’d expect them to be black. This is my graph:

Any clues?

Hello, you should not set Roto’s BG to the source image. Just create merge node and connect mask arrow to the roto. Like this:

1 Like

Omg. That was so easy! Thank you very much!