Ask HN: Image processing, vary intensity of channels

I wonder if anyone can help me please? I'd like to take an image and vary the intensity of the channels separately to show different features. Ideally I'd like to be able to do this in real-time but a batch process to spit out individual frames which could be combined into an animation would be fine. Does anyone have any ideas on how I might achieve this please? I'd be grateful for any help.