Rosin, the magic ingredient without which a bow and instrument are rendered speechless, is a vital element in any string player's tool kit. But do we actually know how it is made, or indeed to make a choice from the multitude of types offered on sale that will suit our playing best? If truth be known, rosin is a mystery to most musicians, and choosing the most suitable product can be as overwhelming as standing in a sweet shop with an overly large choice of chocolate bars to choose from. We are going to explore how rosin works, is made, and explain which types or grades are best for your particular circumstances.
Rosin for the uninitiated
Let us begin with the basics. Rosin is the cake or box of something that often looks to children like the amber in the film Jurassic Park, that is usually found in the smallest compartment within the instrument case. It is often kept in its own small box, or wrapped in cloth that is held together with something that looks remarkably like a small hairband.
Rosin can be called colophon or colophony, particularly by certain luthiers (violin makers), and is derived from resin collected from one of the many different types of pine tree throughout the world. In effect it is made from the sap that oozes from a tree when you cut its branch off, or tree blood, as particularly gruesomely minded children may refer to it as. This product is removed from trees via a tapping process, that in no way causes harm to the trees, in a very similar way to the extraction of maple syrup.
Once the sap is collected, it can be mixed with saps from other evergreen trees, to a secret formula, each being slightly different depending on the manufacturer. Rosin makers are as protective of their own formulas as any confectioner or the producer of popular soft fizzy drinks. The mixture is then strained and heated in large quantities. It is then poured into molds, left to cool, polished and wrapped in a cloth or placed in an individual container. Interestingly, darker rosins will have been made from sap taken from trees in the spring and summer months, whereas the lighter rosins are a product of autumn and winter harvests. The darker rosins are also softer than their lighter counterparts.
Why do we use rosin?
If you take a freshly rehaired bow and draw it across a string, it is highly unlikely that a sound will come out. Gently rub some rosin along the hair, and, just like magic, the bow produces the vibrations needed to make the sound of the stringed instrument that we all know and love. In short, rosin enables the bow hair to produce the vibrations from the string that in turn make the sound that comes out of a bowed string instrument. It is the stickiness of the rosin that stands up the microscopic barbs found along the length of the bow hair, and the resistance that the stickiness and barbs create set the string vibrating to produce a sound.
How to choose
Rosin comes in a variety of grades, ranging from student to professional. The cheaper student grade rosins produce a grittier sound and also a higher level of rosin dust, so can be a disadvantageous choice for players prone to allergies. The way they work and the type of sound they produce can be advantageous to beginners and low-level players, but also can give the extra power and projection needed for the gigging folk or rock musician. The more expensive, professional grade rosins are purer in form and tend to produce a smoother and more controlled tone, essential for some types of high-level performance.
Light or Dark Rosin?
The colour of the rosin has an impact on its performance too. Darker rosins are better in colder climates, whereas lighter rosins tend to be less soft and sticky, and so work well in warmer environments. Darker rosins also work better on the lower instruments of cello and double bass, whereas the lighter rosins create a better response from violins and violas. Bass rosin is the softest of all, and doesn’t work very well on bows other than those used on a double bass, but the other rosins can be mixed and matched a little, so some violists may use cello rosin as a matter of preference and so on.
Precious metal rosins
It is quite common to see gold, silver, lead silver, or copper added to rosin. These precious metals are added to increase the friction caused by the bow, and each has a different tonal quality. Rosin with added gold produces a warm, clear tone, and can often soften a harsher sounding instrument. It is very popular with solo performers who want a clean and defined quality to their sound. Rosin that contains silver is good for a brighter tone and playing in higher positions. Lead-silver rosin is non-sticky, and can add to the warmth and clarity of an instrument's sound, and copper is very helpful when playing smaller instruments, and can create a warm velvety sound.
Hypoallergenic rosins
These rosins tend to come in cake rather than box form, and are low dust producing products. It may be that you need to order this in, although good retailers may hold a small stock for those that tend towards a rosin allergy.
Box and cake rosins
Boxed rosin tends to be lower in price and grade than the caked rosins. The boxed rosins also tend to be lighter in colour, and of a more universal nature. It is a useful product for students playing on synthetic bow hair, rather than horse hair. The caked rosins tend to be higher in both quality and price, and come in a variety of grades and colours.
General tips
Rosin should be used sparingly, and definitely not every time you play. If you find that you are applying more and more rosin, it is highly likely that your bow needs rehairing.
Rosin should always be cleaned off your instrument with a soft cloth after playing, to prevent build up. Don’t forget to clean the bow stick too.
Finally, try not to drop your rosin on a hard surface, as it is likely to shatter in a similar way to glass, create a mess, and need replacing.