you have to duplicate the background layer then adjust the curves on the top most layer. then apply a visible layer mask and paint the core which will reveal the less blown out layer beneath, make a minor gaussian blur then flatten the image https://www.youtube.com/watch?v=K-PC4Sq0Zho
There is an icon with an eye dropper in the curves application. Select this and sample an area first on a dark area and then secondly sample again on the nebulas fringe. This sets the limit on the curve bell an then drag the linear line about this point. You should see the fainter stuff enhance without too much exaggeration elsewhere. Or the best way is to run a mask over the core and integrate another image taken with shorter exposure subs. This is the proven way. Check out some tutorials on curves there should be a better explanation. I’m a visual learner, need to see it to understand it sometimes.
Guys this is a constant question that crops up every year at this time when beginners, and many old hands, try imaging M42. The comments in the posts below and the link to the tutorial should be a Sticky thread somewhere here on IIS.
There are a number of other good Utube tutorials on M42 layer processing that could be linked in as well, if we had a home for them.
Thanks to Nik and Anth for the commentary.
