I was wondering that myself, did a little research and it seems there are mixed opinions. Theres some video footage of fish coming in and hitting the bouncer and then taking off, so some people think its best to leave them unpainted or paint them a dark color. Sounds like some others think of them like a flasher when fishing for salmon, bright color might get them to the area and then theyd be more likely to hit your spinner/bait. Not sure anyone has done a double blind scientific trial on it though, unfortunately. I painted mine a dark color just because I like the look and then the lead wont oxidize and look crappy as soon.