A bow needs rosin to make a nice sound. Here is a little video about applying rosin to a bow.
Key points
- Keep your fingers away from the hair at all times. Over time, the oil from your fingerprints will make the hair dirty and difficult to apply the rosin.
- A little goes a long way. A few long passes along the length of the bow is sufficient. Too much rosin tends to result in a scratchy sound.
- You don’t need to rosin the bow every time you play. Once or twice a week is enough to maintain a good coating, but your ears will tell you when it’s running low.