Thanks fellas
Mike, yes like decon can be, selective brightening of faint features is usually pretty obvious. Hey, I think it is perfectly legitimate and I've done it on the odd occasion, in say a bright busy neb image for example simply for aesthetics to highlight features who's shape is already clearly defined and obvious but doing it to supposedly "reveal" faint extended features is inaccurate and basically pretending. I've seen obvious selective brightening in, for example, images of NGC 1097 to reveal its jets and Centaurus A to try and show the outer hocky stick shaped halo, it is always pretty obvious. In this 253 case of course it was for scientific purposes so any such thing was definitely a no no
Mike