So I've googled and I've come up with at least 10 different methods for getting rid of color casts... and that's all fine and dandy, but what I'm *not* finding which is what I *actually* want to know... is how do you know when you've effectively gotten *rid* of it without having created another cast of a different color? I know there are those color checker charts, but for the sake of my question... let's assume I forgot to use it because it's fairly new to me and I keep forgetting I have it... (Actually, no assumption needed. That's *exactly* what happened. ) When I look at the image I can tell there's too much of a red cast. So I use curves to try and get rid of it... but then when I flip back and forth between my "corrected" version and the original, I can't tell if there's ACTUALLY a blue-green (dare I say cyan) cast, or if my brain is over-compensating for the fact that I was just staring at an overly red image and now I'm not... WAAAAAAAAAY way back once upon a time... when I was first learning how to use GIMP, I sort of remember some method of matching numbers or something in curves in order to get rid of a cast... but at this point I'm not sure if I'm making that up in my head or if that's an actual thing. Does anyone know a sure fire way of getting rid of a cast without creating a new one? Or rather, a sure fire way of TELLING that you effectively got rid of a cast?