Does this sound a little bit weird? What do we do with a discwasher at Statsbiblioteket? And no, there is no misprint: it is not a dishwasher. We really own a discwasher!

The discwasher

Fig. 1: The discwasher. CC BY-SA

In fact, the discwasher is a tool we use in connection with our digitization of 78 rpm record discs. Besides the record player and the digitization hardware and software, the discwasher is the most important tool for digitizing our collection of about 37,000 Danish shellac discs (78 rpm records).

Digitizing the 78 rpm records is not a never-ending story, but of course it is a long-term story. Our audio engineer digitizes about 10 to 12 discs a day (the whole process).

The National Disc Collection

Statsbiblioteket is responsible for the Danish audiovisual cultural heritage. We preserve all music recorded and published in Denmark during the last 100 years, among others all the 78-rpm disc records. As early as 1913, the journalist Anker Kirkeby established the National Disc Collection. Subsequently several Danish cultural institutions stored the collection; at first the Royal Library, later on the National Museum. In 1989 the National Disc Collection was handed over to Statsbiblioteket. This is why we have such a comprehensive, almost complete, collection of Danish 78 rpm records, even though they were produced long before the audiovisual heritage became part of the legal deposit.

The Digitization Workflow

Today I want to tell you about the disc-washing machine, but first, let me introduce you to the whole process – from the disc in the archive to the raw digital record. That will give you an overview of the discwasher’s role in the workflow.


Fig. 2: Checking the discs condition. CC BY-SA


Fig. 3: Putting liquid soap on the disc. CC BY-SA

The first step is to get the discs from the archive in small shares and register that they are now going to be digitized. The next step is to wash the disc. After this the cleaned discs are moved to the digitization room. Here we have two important tools: the recording machine and, just as important, the ears of the audio engineer. He listens to the record – and from what he hears, he chooses one of four different pickup needles for the final digitization. However, this is another story.

Spreading the soap.

Fig. 4: Spreading the soap. CC BY-SA


The aspirator.

Fig. 5: The aspirator. CC BY-SA

Disc Washing

Let us get back to the discwasher. You should not imagine our discwashing machine like a normal dishwasher, where you can add a certain number of discs, start the machine, and an hour later the discs are clean. The discwashing machine looks more like a record player than a washing machine (fig. 1). It takes about ten minutes to wash one disc side. Before washing the disc, the audio engineer checks the condition of the disc; are there any marks, scrapers, fingerprints etc. (fig. 2)? He registers his observations in a database. Then he adds a water based liquid soap to the disc (fig. 3) and uses a very soft brush to spread the soap (fig. 4) in order to dissolve dust and fingerprints from the disc. Next step is to remove the soap again. To do this he uses the pickup arm. In fact, this pickup is not really a pickup, it is a kind of aspirator (fig. 5 and 6), which absorbs all the fluid and pipes it into a bottle attached to the washing machine. Finally, the audio engineer carefully removes the clean and dry record disc from the discwasher and turns it around – and; Same procedure for the other side of the disc.
How long does it take to wash a disc? Our audio engineer washes about three to four discs per hour.

Removing the soap.

Fig. 6: Removing the soap. CC BY-SA

Soap container.

Fig. 7: Liquid waste container. CC BY-SA

by Sabine Schostag, Statsbiblioteket