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For ‘The Monk by the Sea’ by Caspar David Friedrich, you will initially find 18 duplicates in the image archive under ‘Similar images’Your text to link here… because they have the smallest vector distance in the image similarity search.
What is behind this? For the image similarity search, a method using image vectors created with the help of the self-supervised learning algorithm SwAV (Swapping Assignments between Views) was integrated. The implementation comes from Facebook, using a pre-trained model on the ImageNet dataset (ImageNet). The resulting vectors were reduced to 80 dimensions, calculated for all images in the archive and stored in the index. Search queries are based on comparing these vectors using Euclidean distance – this displays particularly similar images.
prometheus integrates 17 foreign museum image databases via API, which are provided by the respective museums.
1 Amsterdam Museum, Amsterdam
2 Freer Gallery of Art and Arthur M. Sackler Gallery, Washington DC
3 Getty Museum, Los Angeles
4 Metropolitan Museum of Art, New York
5 National Museum of African Art, Washington DC
6 National Museum of the American Indian, Washington DC
7 National Portrait Gallery, Washington DC
8 Paris Musees, Paris
9 Rijksmuseum Collection, Amsterdam
10 RMN Musée d’Orsay, Paris
11 RMN Musée Du Louvre, Paris
12 RMN Musée National D’art Moderne, Paris
13 Collections Online Albertina, Vienna
14 Smithsonian American Art Museum, Washington DC
15 Statens Museum for Kunst, Copenhagen
16 The Art Institute of Chicago, Chicago
17 The Cleveland Museum of Art, Cleveland, Ohio
We also offer an interface (API) to the prometheus image archive, which can be used to perform actions such as searching, retrieving images, exploring image collections, and uploading images.
In your personal profile, you have 16 settings options that you can use to customise it to your preferences. To do this, first click on your name in the top right-hand corner and then on Settings.
Account
1. Which language do you prefer? English or German?
2. Which feature should be your home page? Simple search, advanced search, your image collections, public image collections …?
3. Which sorting do you prefer? Updated at, Created at …?
4. Which sorting direction? Descending, ascending?
Search
5. Sorting?
6. Preferred view? List or gallery?
7. Number of records per page? 20 – 100?
8. Zoom in on thumbnails?
Image collections
9. Sorting?
Records from image collections
10. Sorting?
11. Sorting direction?
12. Preferred view?
13. Number of records per page?
Uploads
14. Sorting
15. Sorting direction
16. Number of records per page
15 years of Prometheus meant 88 integrated databases, over 1.5 million images, nearly 10,000 personalised accesses and 159 licensing institutions. We celebrated this in 2016 at the conference ‘In, above, below, beyond and in between – levels of digital images’.
Would you like to be informed about news and changes relating to the image archive? Then subscribe to the prometheus newsletter. Every fortnight, you will receive information and tips on digital image worlds, digital research, digital teaching and digital remixing, as well as relevant calls, dates and prometheus figures.
Read our previous newsletters.
When you search in Prometheus, the search is performed across 135 image databases. This is the default setting. However, you can also select which image databases to search in the advanced search. For example, if you group by city, thirteen Berlin databases will be displayed.
We have now integrated a new feature here. You can make a special selection of image databases, for example the 13 from Berlin, save this selection and select it again for a later search or set it as the default for further searches.
You can read more about this in the current newsletter.
Twelve years after its launch, the 1 million image mark was broken in 2013, followed by the 3 million image mark ten years later, and we are currently approaching the 4 million mark. We are confident that we will reach this milestone in our anniversary year.
Today, 11 December, is International Mountain Day, a commemorative day established by the United Nations to highlight the importance of mountain ranges for life on Earth.
So we searched for mountains in the image archive and found a lot of mountain ranges, including via the ‘similar objects’ feature. Behind this is the image similarity search, which was integrated at the end of 2021 and developed and integrated within Task Area 3 of the NFDI4Culture project by Francisco Mondaca and Jörg Koch.
In our newsletter, we have a section called ‘prometheus search terms’, in which we list the top 10 terms from the previous month or the top 10 terms with a specific initial letter (from A to Z) along with the number of searches.
In October 2025, the top 10 were
caspar david friedrich (275) * einhorn (233) * gerhard hoehme (144) * victim (111) * laokoon (106) * gabriele münter (105) * hannah höch (98) * nam june paik (96) * kreuzigung (96) * auguste rodin (96)
and the top 10 h-terms
hannah höch (98) * hilma af klint (78) * herakles (77) * heilige ursula (65) * helios (48) * hiroshi sugimoto (43) * haussmann (40) * hieronymus bosch (39) * hans baluschek (33) * hexen (33).
In nine steps, you can request guest access to test prometheus free of charge for 1 week.
1. Register “Try for free for one week”
2. Enter your login details: Login name
3. Enter your login details: Email
4. Enter your login details: Password
5. Enter your login details: Confirm password
6. Enter your personal information: First name
7. Enter your personal information: Surname
8. Enter your personal information: Research interest
9. Click on the button “Register”.
You will receive access after activation by the office.
