The violin and the art of its construction: a treatise on the Stradivarius violin

by August Riechers

XX. THE VARNISH.

There has been for many years a warm and to a certain extent undecided discussion going on, as to whether the varnishes used by Italian violin makers were oily and slow-drying ones or spirit varnishes. To investigate this matter still further, and to arrive at a correct decision, will have to be left to the future.

I am, however, of the opinion that the old masters made use of spirit or turpentine-oil until the middle of last century, but never of linseed-oil or turpentine-oil varnish, as has been often asserted.

My opinion is supported by the following fact. In the year 1860 I had the good fortune to buy a real Nicolas Amati lute which, although very much knocked about, still retained a thick varnish of a most beautiful gold colour. For my information I took the varnish off, in order to submit it to the analysis of a clever chemist who, being a talented amateur violinist and also a pupil of Spohr, showed great interest in the matter and communicated to me, as the result of his investigations, this fact that among the quantity of varnish which I had placed at his command, there was not a trace of evidence which could lead to the conclusion that linseed-oil varnish had been employed. In my own researches I found that the varnish was immediately dissolved in spirit of only 90 per cent., while in oil of turpentine and linseed-oil it was scarcely affected, and by boiling only a small portion was removed. Again, it is not probable that Stradivarius, in whose workshops about 3000 violins were constructed, would have employed linseed-oil varnish, seeing that it would have required, in each case, six months for the violin to get thoroughly dry.

There are many resins which can be dissolved in spirit or oil of turpentine and used as a varnish, but the preference is generally given to spirit-varnish, as it dries more quickly. If the spirit or turpentine-oil has evaporated, only the resin remains.

The greatest attention must be paid to the relative hardness of the resin and the wood, for both should be of equal density. Hard resin hinders the vibration of the wood, and consequently the quality of tone suffers.

In my opinion shellac is quite useless for varnishing, it being much too hard, but nevertheless it has been employed from 1770 until the present day, in spite of the fact that the best Italian instrument might be completely ruined by being varnished with it. In all Italian instruments the old varnish is always very porous and soft, and can easily be dissolved by the application of spirit, while, on the contrary, it requires great labour to effect the same with turpentine-oil.

Many people affirm that the art of mixing the old Italian varnish which so charms us with its brilliancy and transparency, is no longer known, in fact that it is for ever lost. I am, however, of a different opinion and maintain that our modern varnishes are quite equal to the old, but what we have until now been unable to produce scientifically, is the golden-brown underground which the wood of older violins has acquired through age and other influences. The proof of this I have practically demonstrated by varnishing old instruments with new varnish, in imitation, with such success as to arouse the wonder of connoisseurs, the varnish being quite as transparent and brilliant-coloured as that used for violins in the last century.

To one other point I should like to call the attention of the reader. In repairing old instruments of the time of Stradivarius, I have found that an extraordinary cleanliness and lustre is obtained by rubbing them with fine glass-paper, which is not the case with Tyrolean and German violins of the same period. At a later period this peculiarity was not met with so frequently and from the year 1750 not at all. This fact I primarily attribute to the action of the resin on the wood, being also of opinion that the fine dust of the same gets firmly embedded in the pores of the wood, and in this way, in course of time, a more or less thick coating is formed.

For one of these practical experiments I took a violin which I had made myself and the tone of which, through years of constant use, was therefore quite familiar to me, and gave it a coating of melted resin on the inside. After this was thoroughly dry and hardened, I polished the interior and remarked the before-mentioned smoothness and brilliancy, the obtaining of which firmly convinced me that I had discovered the truth of the matter. Although, after the glueing-on of the belly, all the former conditions of the violin remained unchanged, yet I was astonished to find what a common-place squeaking tone the instrument had acquired, thus proving to me that with the melted resin I had obtained in the end exactly the opposite effect to that which I had hoped for. I was obliged to rest contented with my failure for a long time, when a lucky chance came to my help. It was this. I received a real Caspar da Salo violoncello to repair, which had never been opened and seemed to have been very little played upon, for on it I found an old bridge which I kept as an ornament and curiosity, and which, on closer examination, I found was varnished.

When I opened the cello, it was proved without a doubt that the interior had also received a coating, probably to protect it from dust, etc. The celebrated old violin makers, in so doing, have pursued the right course. This discovery also corroborated my own supposition, that the old masters varnished both the interior and bridge of the instruments they made.

Now, in order to obtain a ground-priming, I paint the violin, when the wood of which it is constructed is in its natural state, three times with pyroligneous acid, with which a golden-brown underground is obtained, then follows a single coating of spirit and balsam of Peru in equal proportions, and after this one or two coats of a weak solution of gamboge or anotta, and finally, over all this I lay on 20 or 30 coats of varnish, according to the thickness required, and which I prepare as follows:—

Dissolve three parts of sandarac and one of mastic in spirit, and in order that it may be laid on more easily, add to each half a litre[1] of varnish, ten drops of oil of turpentine. The colouring of the varnish I obtain from turmeric and bright red sandal-wood by means of spirit, using more or less of it, according as to the lighter or darker tone required; if a brown varnish is required, some soot from turpentine-oil must be added to the spirit.

I have made innumerable experiments with other resins and colouring matters, but in the end I always return to those mentioned above as the best to be used. Dragon’s-blood must not be employed, the colour not being fast.

When the varnish is dry, it must be very carefully polished with finely powdered pumice-stone and linseed-oil, applied with a piece of felt.

[1] Half a litre is very little less than a pint.