Zum Artikel "Bach und Wasserzeichen – Digitalisierung in der Staatsbibliothek"

Bach and Watermarks – Digitization at the Staatsbibliothek zu Berlin


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Everyone has heard of Johann Sebastian Bach, but few know that four of his sons were also musicians. Their works are now being rediscovered – and digitized – at the Staatsbibliothek zu Berlin. Martina Rebmann, head of the music department at the Staatsbibliothek, talks to us about the relevance of Bach and his sons today and the important role that watermarks play in her work.

A research and digitization project titled "Source repository of the Bach Sons " is currently underway at the Staatsbibliothek zu Berlin (Berlin State Library), with funding from the German Research Foundation (DFG). What role did the children of the famous composer Johann Sebastian Bach play in the history of music?

Martina Rebmann: Johann Sebastian Bach had a great many children, and four of his sons became musicians themselves: Wilhelm Friedemann (1710–1784), Carl Philipp Emanuel (1714–1788), Johann Christoph Friedrich (1732–1795) and Johann Christian (1735–1782) all worked as composers and left behind very large oeuvres. From the point of view of musical history, the most important of Bach's sons was Carl Philipp Emanuel, often known as C. P. E. Bach. His stature is due not just to his extensive work as a composer, but also to the fact that he carefully tended the musical legacy left by his father, much of it consisting of works preserved only as manuscripts. In 2014, the Staatsbibliothek zu Berlin celebrated the 300th anniversary of his birth with a special exhibition. For thirty years, he was a court musician of Frederick the Great's in Berlin, and he worked another twenty years as a director of church music in Hamburg.

What have the Bach sons left us?

The composers of that time wrote their music by hand, which is why original scores of this kind are known as autographs. Many such documents are now held by the Staatsbibliothek zu Berlin, and specifically by the music department, which was established in 1842. At the time, the library was one of the first to begin collecting autographs, music manuscripts, and printed music on a large scale, including, of course, the works of Johann Sebastian Bach and his sons.

Were the sons of J. S. Bach able to emancipate themselves from their famous father?

By the time that Johann Sebastian Bach’s sons started to follow in their father's footsteps, his music was already considered old-fashioned. They tried out a lot of new things, which amounted to a leap forward in the evolution of musical style. Their experimentation with new harmonies, types of instrumentation, and genres, produced quite a contrast with the works of their father. They trained under him, but their own style was very different. And as professional musicians and composers, they naturally had to move with the times, too, and respond to changing tastes.

How important is the music of Bach and his sons today?

The music of Johann Sebastian Bach is unquestionably part of the canon of great music – his works are still routinely performed around the world. The music of the Bach sons, on the other hand, is less well known. However, it is receiving more and more attention. Over the last twenty years, research into the sons has increased, their works have been republished, and their music is featuring more often in concerts and recordings. This still largely unknown world is of interest to many who are looking for music outside the established canon. Our project " Source Repository of the Bach Sons" taps into the mood of the moment, because we want to make the source material available worldwide at no charge.

Historisches Schriftstück
C. P. E. Bach: Autograph of the Magnificat Wq 215 (Berlin version 1749), call number: Mus.ms. Bach P 341, first sheet of music. © SBB-PK
Wasserzeichen einer historischen Handschrift
Watermark from the manuscript of the Magnificat by C. P. E. Bach, dated 1749 (stag with tree and foundation) © SBB-PK

Bach Digital III – Quellenkorpus Bach-Söhne

Project "Quellenkorpus Bach-Söhne" on the Website of the Staatsbibliothek zu Berlin

What exactly does the project involve?

Each piece of music is cataloged and digitized according to the international bibliographic standard RISM and then added to the Digitized Collections of the Staatsbibliothek zu Berlin. Scholars, musicians, and publishers can easily access it there free of charge. Our collection is of particular interest to musicians, as we have many old pieces and can offer them the original source material to study. That is important because it often shows, in great detail, how a composer intended certain passages to sound.

How so?

A modern printing of a score is normally very prosaic. The musical notation is printed in black and white, in a simple, unadorned style. But things look very different in the source manuscripts for those works. Although they are more difficult to read, they contain a great deal of information, such as the writing style of the composer, which can reveal a lot about the musical expression of a passage. This information is of great interest to musicians, because modern editions of a score always involve adopting "interpretations" of individual pieces. The original sources contain an absolutely authentic version.

Has your research into the source material uncovered anything especially interesting?

Our research into the watermarks in the autographs is very exciting. In the course of our work on this, we have developed a method which other institutions now use for their own music manuscripts as well.

What are watermarks, and what do they reveal about the manuscripts?

Watermarks have traditionally been used by paper-makers to mark their products when they made sheets of paper by hand. They were created by applying a fine wire mesh in the shape of the watermark to the mold, which was a screen holding the wet pulp that would eventually form the sheet of paper. Fewer pulp fibers would settle on the screen in that area, and the paper was almost imperceptibly thinner there. This allowed more light to pass through the paper there, making the watermark visible – everyone could see which paper-maker had produced that sheet. Since every paper mill had its own watermark, which was changed regularly as the molds wore out, documents can now be dated using the watermark. Paper was very expensive back then; it was generally not stored for long and only rarely purchased for later use. We can therefore date watermarked autographs to an accuracy of within a few years.
For example, if we find a watermark from 1755 in a manuscript – we can determine that by comparing it with other sheets that have already been dated – we can then date that manuscript to between 1755 and approximately 1760. That is extremely helpful, because composers generally did not write a date on their manuscripts.

What is the special method that you developed to identify the watermarks?

The method we developed at the Staatsbibliothek zu Berlin in collaboration with the Fraunhofer Institute Braunschweig allows us to see the watermarks in the music manuscripts using a thermographic (thermal imaging) camera. The watermarks are often scarcely visible to the naked eye, and can be hard to see even when using a lightbox, especially if they are covered by text or musical notation. When thermal imaging is used, thermal energy (heat) corresponding to about 39 degrees Celsius is conducted through the paper and measured with an infrared camera. At the points where there is a watermark, more heat flows through the paper, and the mark is clearly visible in the infrared image.

You are making the digitized material freely available on the Internet according to the open access model. Do you sometimes regret losing control, so to speak, over what happens to the works?

No, it isn't a problem for me that we no longer have that role. That's not our purpose anymore, to be the place that everyone has to come to and ask for access. For the research community, open access on the Internet is a huge gain, if only because digitized content provides unrestricted availability anywhere and anytime. In my opinion, we have a responsibility as a public institution to make our sources accessible to the general public and to scholars everywhere, and open access allows us to do just that. Furthermore, creating digital copies protects the original manuscripts, because they don't have to be taken out of secured storerooms again and again. They stay where they are, protected from physical contact, light, and changes in environmental conditions.

Is open access the future?

It is already the standard practice for digital data in research, which is usually funded with public money, of course, and I think it is a very sensible practice for the reasons mentioned above. At the same time, open access gives rise to completely new synergies and approaches, since unrestricted availability means that data can be accessed by people who never would have come into contact with Bach or the Bach sons otherwise. This can lead to entirely new ideas and uses for the material – and that is an exciting prospect.

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