The ‘Titian Inspired’ violin has now entered the assembly stage!
Monthly Archives: November 2011
What’s in a colour
I’ve begun looking at pigments to colour the ‘Titian’ Strad I’m making. From the ‘Pigments through the ages’ website, we can see that brown, yellow, and red pigments used in the 1650-1750’s included:
- Lead-Tin Yellow 15th-18th Centuries. Lead stannate (Type I), Lead tin oxide silicate (Type II).
- Indian Yellow 15th-19th Centuries, Magnesium euxanthate.
- Vermilion (aka cinnabar) 8th Century on. Used by the painter Titian, the color of whose paintings inpsired the naming of the Titian Strad. Mercuric sulfide.
- Red Lead (aka minum) Lead(II,IV)-oxide.
- Orpiment (aka King’s Yellow), Arsenic sulfide. Used in Asia and Persian, but not Northern Europe.
- Realgar, Toxic Arsenic sulfide.
- Madder Lake (Natural: garanza lake, Synthetic: Alizarin), most widely used in the 18th and 19th Centuries. Often refered to as the colour used most often by the Cremonese makers.
- Yellow Ochre, Iron oxyhydroxide.
- Red Ochre, Anhydrous iron(III)-oxide (Aka Cinabrese, Synthetic: Mars Red).
- Umber, comes in Raw Earth and Burnt varieties. A natural mixture of iron and manganese oxides and hydroxides.
- Carbon black, (aka Charcoal black, vine black, lamp black).
- Bone Black (aka ivory black, bone charcoal) It contains about 10% carbon, 84% calcium phosphate and 6 % calcium carbonate. It is made from charring of bones or waste ivory and has a black-blue hue.
These are period pigments and all are very light-fast. Other organic dyes can be extracted from a variety of plants, etc, but in those cases you have to weary of fading.
Note that some of the above are opaque pigments and some are translucent. Opaque’s are good for touching up blemishes, but should be avoided for varnishing new instruments.
For the current instrument, I’m exploring Vermilion, and Alizarin (Madder Lake). Here are some colour samples. I’m using synthetic pigments based in linseed oil.
Chladni and the his infamous patterns
Chladni patterns are visual representations of the nodes of vibrations setup in the a surface while it is subject to a specific frequency. This and more on modern acoustics is found in Chapter 5 of Erik Jansson’s publication “Acoustics for Violin and Guitar Makers” here. A good overall description of Chladni patterns can be found on the New South Whales University website here.
Ernst Florens Friedrich Chladni has been around a while and published a book on the patterns seen in vibrating plates in 1787. His original publication is on Google Books here, however, a knowledge of old German and a Ph.D. in physics are prerequisite. It’s reported that his interests in the patterns were inspired by George Christoph Lichtengberg’s earlier experiments on electrical figures. Interest in this visual representation of sound waves was such that Chladni demonstrated it for Nepolean in 1809. A plate of the image of Chladni is seen below .
Brain, Robert Michael, Robert S. Cohen Ole Knudsen, Hans Christian Orsted and
the romantic legacy in science: Ideas, disciplines, practices, Boston Studies
in the Philosphy of Science (Springer: 2007) p238
Stockmann, Hans-Jurgen, Quantum chaos: an introduction (Cambridge Univeristy
Press, 1999) p15