After reading previous threads on prop painting, affecting balance seemed to be the primary deterrent. I was meeting several families with lots of kids at the river and wanted me to fly my drone for them so to add a little flair, I decided to use red and black sharpies to give the props a cool look and have minimal balance effect. Props are very visible up to 10-15', props are turning so fast that you only see the red and black bands. And there is no affect on balance or vibration, downside is the color is so thin it doesn't hold its color very well, pic is after month of use. And its obvious it was a rush job, but the kids loved it and nearly all of them wanted to fly the darn thing, which I had to decline (I've crashed and put so many in the water already, I just didn't to be out shined)