Have you ever wondered about the color and finish of your instrument? We often think of our instruments in terms of their construction, hardware, strings and the like, but the beautiful, protective coating of our instruments is often forgotten.
And while many of us don’t give a second thought to the finish on our instruments, some luthiers value it enough to spend their whole careers perfecting their recipe and application of varnish. Some luthiers even believe that the “magic” of Antonio Stradivari’s instruments is in the varnish he used, and they’ve made it their life goal to replicate his formula. What do they know about varnish that we don’t?
First off, they know varnish is more than just a pretty covering. The finishing process serves to protect the wood of the instrument from its environment. Without it, the wood would be left directly exposed to contaminants like sweat, oils, moisture and dirt. Wood does not fare well in contact with such things, thus varnish.
Protection is not the only function of varnish, however–it also colors and beautifies the wood. Varnish doesn’t accomplish this in the same way a wood stain colors furniture, however. Instead, pigments added to the various layers of varnish color the instrument without penetrating the wood. This is why scratches reveal pale wood beneath the color. (On that note, if your instrument gets scratched, don’t try to stain the exposed wood! Take your instrument to a luthier, who can re-apply varnish and color to the area without damaging the wood.)
Every luthier has his own special process for varnishing instruments. No two methods are the same, and the exact steps and formulations are often carefully-guarded secrets.
A typical varnishing process (minus all the secret ingredients, techniques and incantations) begins after the body of the instrument is entirely constructed and glued together. The instrument has no fingerboard, tailpiece, bridge, tuning pegs or other hardware at this point. Often the very first thing to be applied to the instrument is a solution of tea or coffee that reacts with the tannic acid in the wood and begins to bring out some color.
Next is a clear “ground” coat that penetrates and protects the wood, forming a barrier that prevents the varnish from soaking into the wood. Historically, this initial coat contained high levels of minerals and was made of organic glues and gums, among other things.
After the ground coat, the luthier will begin to apply the color coats. The pigment can be high-quality artist’s oil paints, or natural substances like plant root ground fine and mixed with oil. In order to color the instrument, the pigment can either be applied directly to the instrument and followed with a thin coat of clear varnish, or mixed in with the varnish itself. The decision is driven purely by aesthetics, as both approaches are effective yet they produce a slightly different look.
Once the luthier is satisfied with the color, he or she will add a couple more coats of clear or very light varnish to seal and protect the color coats. This enables the luthier to polish out any brush hairs, bugs, or other debris from the surface without disturbing the color coats.
Varnish and Value
Though microscopically thin, varnish has a pronounced effect on the sound of the instrument. A good varnish is hard enough to protect the instrument from damage, yet soft enough to allow the wood to resonate. A varnish that is too hard will dampen the vibrations of the wood, keeping the instrument from sounding its best. Think of a ballerina trying to dance in a suit of armor.
The trade-off between durability and resonance becomes obvious if you compare a student instrument with a premium-quality one. The student instrument will usually have a very hard, shiny finish that is designed to handle abuse. A hard finish doesn’t allow the wood to vibrate freely, though, which can contribute to poor sound. The nicer instrument will have a softer varnish that is more susceptible to damage but allows for freer vibration and optimum sound.
Part of the art of making quality instruments is applying a varnish that is just the right hardness.
The very best varnishes from centuries past were quite soft and fragile. Some were formulated in such a way that they were (or still are) in a state of constant chemical flux, interacting with the environment and changing all the time.
The varnish on an antique instrument greatly affects its value. An instrument with intact original varnish is rare, because normal use can wear it away in a matter of decades. A fine original varnish is a beautiful sight, as it can develop a lovely effect called craqueleur. Craqueleur is produced by the layers of varnish expanding and contracting at slightly different rates, causing the surface to form tiny cracks. These can be so small that the surface of the instrument takes on a matte appearance, or they can be clearly visible as tiny interconnecting grooves in the finish.
This sign of excellent varnish can take a hundred years or more to develop, and sadly it is often not recognized for the wonder it is. Well-meaning people sometimes buff or polish out the craqueleur in favor of a shiny appearance, irreparably damaging the varnish and reducing the value of the instrument.
Caring for Varnish
Varnish can be ruined by well-meaning owners who polish it too often. Polishes typically work in one of two ways: either they shine the instrument by adding a thin coat of material, or they use a fine abrasive to remove a thin layer of varnish from the surface. Both methods will ruin the finish over time, one by building up a thick coat that inhibits vibration and the other by eventually removing all the varnish.
Instruments do need to be cleaned, but the best approach is to skip polishing altogether. Instead, take your instrument to a luthier on occasion to have the dirt and rosin buildup removed without damaging the varnish.
Like our skin, a good varnish protects your instrument, gives it its unique appearance, and allows it to move and vibrate freely. And like our skin, varnish deserves special care and attention to make sure it stays intact and beautiful.
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