Varnish

The mystique of violin varnish centers around both the luminous beauty it can lend the surface of the wood, and the supposed effect it has on the sound. The acoustical benefits of old Italian varnish have probably been exaggerated – there are a great many antique instruments with almost no original varnish left, but whose sound remains unimpaired.

One of the principal functions of the varnish is to protect the wood. It does this both by binding the surface – helping to prevent hairline cracks from developing – and by absorbing the effects of abrasion and superficial damage. Another important function of the varnish is in slowing down the transference of moisture between the wood and the surrounding air.

An overly soft varnish may mute the sound, especially if it is laid on too thickly, and it can be prone to stickiness. When a varnish is too hard, the sound may become harsh. Brittle varnish will tend to chip off.

An ideal varnish would have a certain softness and lasting flexibility, adhere well to the wood, and be laid on with appropriate thickness. These characteristics would all contribute to good sound and the rather intangible quality of “aging gracefully”.

Varnishes are often divided into two classes – oil and spirit. The first contain some percentage of a drying oil, such as linseed or walnut, and dry by chemical changes upon exposure to light and air. Spirit varnishes, on the other hand, are solutions of resins such as mastic, seedlac or sandarac, in a solvent such as alcohol. They dry by the evaporation of this solvent. Each type of varnish has its advantages and disadvantages.

Current research suggests that the great classical varnishes contained oil-soluble resins or balsams, often combined with some smaller quantity of a drying oil. All these materials had been used for centuries by painters, and their properties were well understood. Alcohol-based spirit varnishes did not come into widespread usage until the late 1700's, and their adoption marks the decline of the classical period of violinmaking.

Traditionally, a golden or amber-colored ground is the starting point in the varnishing process. As woods, oils, and many resins undergo a pronounced yellowing over time, it is uncertain how much of the yellow component seen on old violins is due to age, rather than to the original intention of the violinmaker.

One or more coats of colored varnish are usually applied on top of the ground. The final color is a matter of taste. Current taste leans towards the more muted colors of antique instruments, though this could not have always been so. Stradivari was a pioneer in the adoption of brighter shades of red. As he often worked for nobility, this choice of colors perhaps reflects the type of interior decoration favored by his clients. There may have been an element of status involved – vivid hues required dyestuffs that were expensive at the time. Their extravagant use was a sign of wealth. At any rate, transparent and vividly colored pigments were widely available to painters of the seventeenth century, and they were certainly used by the classical violinmakers.

The bevel of the scroll and the corners of the ribs are sometimes covered with black ink. This accenting of the lines first appeared on the instruments of Stradivari and Guarneri del Gesu, though most of evidence of it has by now worn off their instruments.

Antiquing the finish of a new instrument is a practice which goes back hundreds of years. When handled well and without dishonest intent the effect can be delightful, although many musicians prefer a new instrument to look new, just as the classical Italian instruments once did.