Most efficient way to change color?

Hi folks,

I'm messing around with a cool little app called JSPlacement, which can create geometric patterns of various kinds and complexities.

What i am getting out of it is black and white images (no gradients), just pure black or white geometric shapes.

My question is: what is the most processing efficient way to bring this image into Fusion and change the white color into some other color and the black into pure transparent?

I've found one way to do it, using a luma keyer into a background (mask input), but i'm wondering if there's another way that might be more efficient and uses one less node?

I was hoping i could just plug the image directly in to the background mask input, but no dice!

Use a background node to generate the desired solid color for the whole frame then plug the B&W image into its mask input.

On the Settings tab of the Background node, set Channel to Luminance.

Perfect, mille grazie!!