As I develop more custom brushes from scanned brush marks it increases the vocabulary of what is possible.
Coverting Brushmarks into Photoshop brushes: IMAGE/MODE/CMYK
IMAGE ADJUST/ BRIGHTNESS & CONTRAST / Increase to make background whiter.
IMAGE ADJUST/SELECTIVE COLOURS/ Drop out the whites.
Select Brushmark with space around edges / EDIT/ DEFINE BRUSH / Name.
TOOL PRESETS / NEW / Name.