Affinity Photo Use Selection Tools To Help Make A Shaped Layer Mask

Carl -- could you use a High Pass filter to define the edge of the bulb better so that doing the selection would be easier? If it does a better define, then maybe the brush selection tool would work also. I have been watching many of Simon's tutorials and I wonder also if some of the ways he does groups and adds layers of color just to work on a particular area might be another option. I don't know and that is why I ask as I am trying to learn all I can about AP and it is very challenging.