I had been working with my 1703 Stradivari violin model for a while and got the urge of starting a new instrument, I chose a well preserved 1714 Stradivari which I know sounds great and about which I have all the information I need.
Steward Pollens book “The violin forms of Antonio Stradivari” is an excellent resource when it comes to identifying an outline tracing of a Strad- which means to find out on which specific mould the violin had been made. The original moulds being preserved in the Museo Civico in Cremona together with other artefacts of the Strad workshop were descriptively named by their creator- one form called “PG” would stand for “piu grande”- “a little larger”. The name, often the date and notes for each mould are either written on the wood with ink or cut into the surface. Here is a photo from the book showing the P-form.
To find out which original mould I am working with when choosing a model I check my tracing and outline templates by imposing them over the original moulds presented in the book.
Since I use tracings of the original outlines which are typically assymetrical in their left and right half I try to correct some of these quirks. These deviations are naturally created during the making process rather than being part of the initial design. All the curves in a cremonese violin are made up of segments of circles- to have this in mind makes it easier to understand how the shapes come together.
Between my 1703 model and this new 1714 violin some slight differences in the outline are to be seen. To make it clear I did a tracing of one template and placed the other violin template above it. I hope the differences show up well enough. (1714 drawn on below, 1703 template placed on top)
The 1714 violin fits very well with the P-form (this is the form pictured far above). Upper and lower bout of both my models correspond well with one another. The main difference is to be seen in the C-bouts, which for the later violin are a bit longer as well as more upright and straighter, which gives the violin a more masculin look. I assume they have been made on different forms (since the P-form is dated 1705- too early for my 1703 model). However it is important not to forget the influence of the blocks. If you look at the last photo, this change in outline shape could easily be created by leaving the corner block slightly proud of the from. It is often subject to speculation matching a violin to its form. A lot of the changes in shape from the mould to the instrument happen during the making process which is another thing to consider. Stradivari was a very meticulous maker, over his long working life he made up a large number of moulds form his busy workshop- as the foundation for each new model if he felt the need to change the outline from one to the next instrument. Guarneri del Gesu on the other hand is said to have used 2 or 3 moulds for his whole career (none of them still exists). The outlines in some of his instruments show drastic variations. One explanation which sounds plausible is that he changed his models by simply working the blocks differently rather than spending the time on making a new form.