Thanks Rick. I downloaded and installed the ColorMask script developed by Rick S. It is very easy to use and I think it has enormous potential for enhancing the colours in astronomical images. My hunch is that I will end up using it for RGB and LRGB images, as well as narrow band images.
Most of the elites on this forum have probably already scrolled down to “Free Download: Extra material”. I am catching up, slowly.
http://www.springer.com/gp/book/9783319256801
Best wishes, Murray