Shader graph - overlapping colors do not blend correctly, instead blending with grey in the middle

Hi there,
I’m making a shader that replaces the colours in the red and blue channel respectively and then adds them together. However, any areas where the two colours should mix, they don’t.

The result I expected on those areas would be a gradient like this:
201169-image-2022-10-26-171816160.png
Instead, the blended areas are just black, like on the image below:

How can I make the 2 colours blend correctly?

I attempted to solve this issue by swapping the order in which I was doing things. Doing the multiplies first makes it so that the areas in the red channel that are not vibrant red, blend with black creating the grey colour.


The problem is that this works nicely but not with all colours… Lighter colours display very differently, like so:

So I’m still digging for a solution. Any help would be much appreciated!