Piano key painting

Hi everyone, I was wondering what is the most efficient, easy way to paint the piano keys while keeping the spaces between them green (ESB).

Green first then hand paint the reddish ? Or maybe some type of masking ?

Thanks for any help.

no masking.
paint it all green, then paint the keys with a brush.
TOPS ONLY- do not paint the sides.

Not only is it easy and efficient, it's also accurate

Thanks very much slave1pilot, I had thought the sides were reddish as well. I have seen some pics on TDH where the entire band of the key area was painted, I knew that was incorrect, but I couldn't tell about the sides. Makes life easier !

I appreciate the help,

Timmer