For painting blades with a full coverage, i'd stick with plain blades rather than hammered.
First time i tried painting blades - i painted a bunch in solid colors - both smooth finish and hammered. Loved the way they look in my hand, but when you run them on a sunny day, they seem like they get lost. Just don't have the FLASH any more which is half the attraction IMO. I'm sure a black painted blade is going to cause attraction just from the water it pushes, but once it starts spinning it is almost invisible...... to my eyes anyway.
Hammered blades are 'spose to put out a little more flash than plain blades since they have more angles and edges to bounce light. Take advantage of it by painting your blades in a super light coat of candy or translucent color. It will let the reflective silver blade still keep the flash...... but it will now be a different color flash.
Just my thoughts anyway.