ctanzio

Hopefully, some will post their experiences with coloring oil varnishes. My experience is adding colorants to oil varnishes is a method filled with challenges. But I can give you some basic information about the differences between dyes and pigments which may help you decide how to select a colorant. A dye dissolves into the varnish and, in general, forms some kind of chemical bond with the varnish and/or the wood. A dye absorbs some narrow band of visible light. The light that is not absorbed determines the dye's color. This light passes through the varnish to the wood surface, where it is reflected back to the eye. So dyes are transparent and do not obscure the detail of the wood. Dyes require certain specific chemical structures to be present in the molecule. If any one of these structures are altered or destroyed, then the color fades. UV light is notorious for damaging these structures. So many dyes, especially ones extracted from plants, tend to fade. A pigment is a solid that is suspended in the varnish. So particle size is an important consideration. Some pigments may require a special binder to get it to suspend uniformly. Artist oil paints are mostly a linseed oil-based binder with finely ground pigments suspended in it. There can be other additives that do not play well typical oil varnishes. Like a dye, a pigment absorbs some narrow band of visible light. But it scatters the remaining light. Some may reach the surface of the wood where it is reflected back up to the pigment to be scattered once more. So pigments are translucent to opaque depending on how much pigment is in the varnish. The wood detail becomes increasingly obscured. Pigments are mostly stable chemical structures. Therefore, they are resistant to fading. Good luck!

I saw this video ages ago when I was active on violinist.com. I found it fascinating for two reasons: 1. A master violinist talks about the sounds he wants and then proceeds to play in a way that creates the sound. He spent years practicing his craft and can evoke glorious tones with seemingly effortless ease. 2. A master violinist attempts to give scientific explanations for how a violin works after fiddling with a few parameters. It is a case study in post hoc fallacies. For the player, it is filled with interesting ideas to try with bow and finger. Example: driving the string to get a bit of growl in the tone without muddling the sound. For the luthier trying to setup and troubleshoot a violin, not so much. Examples: string afterlength adjustment and "playing in" the wood.

I do enjoy playing viola. (>GASP< I know. I am opening myself up to public humiliation.) The music definitely gets transcribed to the key of C then. For an older amateur player like myself, whose hands are suffering from the ravages of time, G/Em on a violin and C/Am on the viola require just two comfortable hand shapes to get a full two octave range from first position. Also, a variety of common double stops and drone techniques remain practical. C/Am on a violin requires three different hand shapes and an awkward stretch or a small shift to get a full two octave range and practically eliminates most of the G string from a tune. Also, C on a G string is frequently afflicted with tonal challenges from a common "wolf" note found in that area. This is not a good thing for the tonic note of a tune. This concludes the first installment of Tanzio's hacks for players trapped in first position.

Thanks for those observations David. In practice, I never play anything above 1st position by avoiding tunes with more than a two octave range and using the auto-transcribe feature of MUSESCORE to shift the key to G Major.

I found the most interesting part of the video to be the comparison of harmonics for the same note played on different strings. It suggests that the higher harmonics become weaker the higher up on a string you play a note, at least for the test conditions of the study. So an open A has a strong response across much of the several initial harmonics. The same A played on the D string shows some weaker response in the higher harmonics. The same A played on the G string show even weaker response in the higher harmonics. It was suggested that it might be due to the decreased vibrating mass of the shorter fingered strings, but I didn't notice any strong evidence or reasoning to support the conclusion. Still, an interesting demonstration as to why fingered notes can sound weaker compared to note played on open strings or in lower positions.

Again, this is just a fundamental misunderstanding of vibration. Resonance is a frequency at which a structure vibrates strongly. A structure can have multiple resonances, called natural modes of vibration. These modes are affected by geometry, stiffness and mass. Changing any one of them can change the frequency and strength of one or more resonances. Tone is a psychological reaction to the sounds being produced by what each resonance contributes to the movement of air around the violin. Which is why discussions about the goodness or badness of the tone of a violin is so subjective. If there is any objective standard to tone, it is based on common reactions to sound that we all share as members of the same species.

One example: Transtint dyes added to shellac as a toner, then finished with oil-based varnish have not faded for me for objects subject to normal indoor use. Some pieces, including a violin, date back to about 10 years. Don't know how it would fare under extended direct sunlight or in a UV cabinet. My experience is limited to browns and reds.

I think you might have too simple an idea about what the phrase "combined together" means for a vibrating structure. Suppose you play an open A string. The string will vibrate at 440hz, 880hz, 1320Hz, ..., n x 440 Hz for n = 1, 2, 3, ... These are called the string harmonics and they drive the response of the violin. Now pick anyone of those harmonics, say 440Hz. All the NATURAL modes of the violin will vibrate at 440Hz, even though NONE of the natural modes may have a frequency of 440Hz. The amplitude of the vibration (volume level of the sound) is affected by how far apart the string frequency (440Hz) is from the natural frequency of a mode. The phase of the vibration is also affected by this but also by the damping of the wood. Modes vibrating out of phase with the string may decrease the volume and the shape (tonal quality) of the sound. All the natural modes vibrate at the string harmonics, but may add or detract from the volume or change the tonal shape of the sound. As a general observation, a plate mode affects the sound of a note whose first few overtones are within +/- a few octaves of an overtone. That pretty much covers all the significant modes (a range that tops out at around 3KHz), and also covers the typical playing range of a violin. This is why many of the more successful makers do not have a high opinion on focusing on specific modes or tap tones. It is more important to get the weight and shape correct to get a balanced volume across a lot of modes. Adjusting a single plate mode is not going to turn a mutt into a pure bred.

I do not use oxidizing agents. I do an initial ground with highly diluted blonde shellac. If the wood is too light, I will add a color coat with some diluted blonde shellac with high quality alcohol-based dyes, or use a few coats of diluted amber or garnet shellac. Then finish with oil-based varnish.

Your basic understanding of how violins vibrate is mistaken. The violin has many natural modes of vibration. Some have the belly and back strongly coupled. Many do not. You might want to investigate the many papers written on the vibration modes of the violin. The internet is an amazing resource.

It is important to note that the chemistry of wood oxidation is complex and can involve both the tannins in the wood and the various sugar complexes of the cell walls. Simply mixing a bunch of chemicals together willy-nilly and brushing the solution onto the wood can yield wildly varying results. Try to find a scientific paper on the specific type of chemical treatment you want to try. Then carefully follow the solution preparation and application steps. For example, poor preparation of the popular steel wool and vinegar solution can result in an intense red liquid with lots of red gunk that is mostly rust and Fe(II) based compounds. Even after filtering, the resulting reaction with wood tannins can be weak and fading. But a preparation to fully dissolve the steel wool while also drastically reducing the amount of solids precipitating out of the liquid will yield a light red solution very high in Fe(III) concentration. This will drive the tannins into stable macro-molecules with strong color changes.

Yup. Now if only I would listen to my own advice. >blows dust off of violin sitting in dark corner of practice room<

If only it was that simple. The stiffness properties of wood change under repeated vibrations only when the vibrations have a significant amount of force driving them. At the force levels experienced by a typical violin from the vibrating strings, the wood exhibits no scientifically detectable changes. Creep and fracture caused by humidity and temperature swings and careless handling and setup should be your main concerns. The absolute best way to improve the sound of your violin is to practice.

Chemical oxidation of wood is a dangerous business. Even when taking the proper handling precautions, the wood prep and finishing steps, if not done right, can ruin the effect. Here are some common options in order of increasing danger that can yield great results, but I strongly urge you to investigate the processes thoroughly before attempting them. - vinegar and steel wool with optional tea or coffee pretreatment - potassium dichromate - sodium hydroxide - fumed ammonia The vinegar/steel wool option is a combination stain/oxidizing solution so requires special care when finishing the wood after treatment. The others will oxidize the wood through the surface and will be highly resistant to changes due to aging. There is a lot to be said about using modern, high quality, alcohol based dyes or simply stuffing the wood in a UV box for a few days. Or go with a tried and proven commercial treatment like in Joe Robson's post. Good luck!

I must decline to answer on the grounds that such conversations may lead to questions regarding paternity that I am not prepared to answer. It was the 70s. Who remembers anything from the 70s?