spot effect

Wondering if anyone else has used the spot effect in X. I used to use the Facelight plug-in with 7 if I wanted to add light to my interview subject and the background seemed too bright. I like the spot effect in X, but it seems to add yellow - or maybe just saturation - to the image even though the parameters don't have any color component to them.

I've played around with it since my original post and discovered that it starts off looking funky color-wise when you apply the effect, but tweaking the amount, etc. will take care of the issues.