Nebula in natural color. Narrowband channels are mixed to match visible spectrum. Red=80% H-alpha+20% S-II, Green=O-III and Blue=80% O-III+20% H-alpha to compensate otherwise missing H-beta.
I have shot this target with much wider field last year;http://astroanarchy.blogspot.com/2009/02/ic443-in-hst-palette.html
I took colors from this image and use them with my new H-alpha channel to build a narrowband color image.