Blend exclusion affects alpha

Hello,

I have an issue using the blend exclusion material node. I want to remove a color from a texture. My material works so far but really reduce the alpha of the original texture. Take a look :

As you can see the final result is too much alpha blended and I don’t understand why, do you have any ideas to do what I want to do ?

Finally I found how to do this. Here’s a screen for anyone interested.