Violin rosin
The question is often asked: Which violin rosin should I use? The following helpful information is provided by Pirastro:
1) High quality rosin enables perfect bowing without scratching, especially if only a thin layer has been applied. In general:
Violinists and violists need a harder or dryer rosin
Cellists need a medium rosin
Bassists need a softer, more sticky rosin
2) Another factor influencing the choice of rosin is the kind of core material of the string you use:
Steel strings can be better played with a hard or dry rosin
Synthetic and gut strings can be better played with a softer rosin
3) Experienced players tend to prefer softer rosin for the studio but harder rosin in the concert hall. Hard rosin is best in tropical climate and soft rosin in a colder climate.
4) Rosin does dry out and lose its characteristic formula so it is recommended using a cake of rosin for 1 year only.
