[sharkbite]

Hi Folks - hoping someone could help me.

Just starting on this deep sky lark, i have managed to get a decent stack of Eta Carina subs, stacked them in DSS and created a star mask.

As i am way too tight to pay for photoshop...

I was hoping someone might be able to give me some practical instructions on
how to use star masks in either GIMP, paint.net (or perhaps another freeware tool) to reduce the brightness of the stars while increasing that of any nebulosity...

Google is supposed to be my friend, but i have only found tutorials on photoshop...

Any help would be most appreciated.