You need a good dose of criminal instincts to decipher such marginal notes: Decades ago, auction houses used them in catalogs to note important information for internal use that was incomprehensible to unauthorized persons.
If it is successful, relevant information for art trade and collection research, especially provenance research, can be found in the “hand copies”: names of consignors and buyers can come to light, limit, estimate and hammer prices as well as declines.
Material of this kind from the Munich auction house Hugo Helbing, which was active from 1887 to 1937, is extremely interesting because the house, including branches in Berlin and Frankfurt, acted as one of the most important in Germany in Europe - until the National Socialists reprisals Helbing, who was a Jew suspended, forced him to give up his business and finally caused his death.
Helbing's business documents seem to have disappeared, but luckily more than six hundred of his annotated catalogs ended up at the Central Institute for Art History (ZI) in Munich.
In 2016, the Rudigier art dealership gave a swing, and in 2021 another bundle was added, which was found in the basement of the Karl & Faber auction house and handed over to a Helbing heir.
He left it to the ZI on permanent loan.
Including other holdings in Switzerland, a total of 1064 hand copies filled by Helbing himself or his employees with the valuable notes that were once reserved for in-house use were digitized by the Heidelberg University Library as part of a project by the German Research Foundation (DFG) and placed under “German Sales” on the platform "arthistoricum" to be put online.
They are publicly available there.
But without the scientific research done by Theresa Sepp at the ZI, you wouldn't get very far.
What the project manager found out is impressive, and deciphering the various Sütterlin manuscripts was the smallest challenge.
Rarely does everything come together as nicely as in the protocol catalog of one of the auction house's most important auctions, the collection of the industrialist and patron Oscar Huldschinsky.
Helbing organized it with his Berlin business partner Paul Cassirer in 1928 in the Marble Hall of the Hotel Esplanade: a social event and a treasure trove for the international elite of art buyers.
Houses such as the Rijksmuseum in Amsterdam bought old masters, and well-known dealers such as Colnaghi from London or Knoedler from New York also bid.
The fact that some of the annotated catalogs also include first names and places of residence in the name entries can help in the search for objects sold during the Nazi era as a result of persecution.
The digital combination of several copies of the same auction catalogue, which different people annotated in different ways, made "relationships recognizable and puzzles solvable," writes Theresa Sepp in a blog post about the strangest code she was able to crack.
Again and again, the scientist noticed combinations of letters that were recognized as coding for limit prices, but only became legible through catalog copies with numbers in the same place.
R stands for 1, an i for 2 – after all, the word “ox head” represents nine digits, supplemented by H for 0 and HE for two zeros.
The researcher suspects that when Helbing invented this code, he had Aleph in mind, the first letter in the Hebrew alphabet, which resembles a stylized ox's head.
Of course, it is still unclear why Helbing coded limit prices at all.
The scientific processing of the catalogs could be pushed further, the search functions expanded to 350,000 ticket numbers.
The money was available for a year of research,
The digitized personal copies are not only important for provenance research.
With their help, economic issues can also be tracked, such as the development of the market value of artists or categories.
You can research for catalogs raisonnés or find out a lot about art trade networks, also about the strategies of Hugo Helbing's business.
At an online colloquium on the subject, art historian Anna-Lena Lang recently shed light on "cooperation and competition" between business partners Hugo Helbing and Julius Böhler, with the latter playing a dubious role in the company's final years.
Director Bernhard Purin explained what the catalogs say about the Judaica specialist Theodor Harburger, to whom the Jewish Museum in Munich is soon dedicating an exhibition.
And the archaeologist Georg Gerleigner explained how he was able to assign numerous items from the Erlangen antique collection to the previously unknown Georg Dehn collection, which was sold under Nazi pressure.
Such examples from research underscore the importance of the sources, which have been neglected for decades and whose development is likely to cause some surprises.