I want to be able to change colors across my entire image. Kind of like the bucket tool when it is on universal, but with a few changes. It would be able to change dark red into dark blue and also light red into light blue at the same time when the tool is used. It would scale based on the lightness of the color throughout the entire image. I could basically choose blue, click on any red part with the tool, and then every red color (with a certain tolerance) would change into blues of the same lightness and darkness as red. I was thinking that this would be useful for changing the colors of objects that have certain shading effects or shadows in them. I'm not sure if this has been made or if anyone can, but I'd like to know how and if it's even possible.
