I normally add a curve layer to an image, invert it and then use the brush tool to lighten or darken certain areas.
It was working perfectly well and then stopped all of a sudden. When I use the brush tool, nothing changes. I must have accidentally done a shortcut and changed the setting but I have no idea what I did.
It looks like you have the layer mask targeted which is all Black and your painting with black. Change to white paint.
Oh gosh I knew it was something simple!
That worked. Thanks so much for your help.