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The second part of the evaluation of our survey focuses on “image quality”. Regarding the question “How do you rate the quality of the images, the quality of the digital copies (resolution)” on the scale “very good – good – usable – rather bad – very bad – no answer” we received the following answers:

We rougly clustered comments we have received on the topic:
„image quality“
- You can often find images with better image quality when searching Google images.
„differences in the image quality“
- Image quality very, extremely different, varies greatly – from very good to very bad, some very good, others not usable. (several comments) – Quality of the artwork varies greatly across multiple offerings of the same image. The question remains as to which image is closest to the original.
- A “sometime like this, sometimes like that” would fit well here. The quality of the images sometimes differs significantly. No general judgment is possible. The differences are particularly noticeable in objects that exist in countless variations, but you also notice the fluctuations in quality in works that only exist once.
- Some of the images are scans from catalogs which unfortunately have poor quality.
- Often cropped incorrectly.
- The vast majority of images are razor-sharp (in this respect, they could be called very good rather than good). A few undercut this standard. If I ever come across one of these, I usually report it too.

You have two different options in the image archive to share your comments about image quality.
(1) Share your findings directly with the source image databases. Under “details” for the image you will find information about the image database and three icons. By clicking on the middle icon you can “send an email to the person responsible for the database”.

(2)You can also use our rating function to assess the quality of the images.
These ratings influence the ranking when displaying the relevant search results. In addition, the ratings and the number of ratings are sorting options that you can select for displaying your search results list.

Another theme of your comments are the
„differences in color, brightness“
- quality varies greatly and I don’t have a reference model (color wedge) to judge whether the colors are correct.
- sometimes there are differences in the color representation of the same painting and the big guesswork begins as to which one is closest to the original.
- resolution is very different, color calibration of different versions is sometimes so different it’s enough to drive one to despair.
- some of the same works in different chromaticity; makes it difficult to make out the original color.
- There are digital copies of old slides with the rot disease, there are very good ones, especially by large museums. It is a matter of luck.
- Overall, the images are sometimes of very poor quality, especially when it comes to color accuracy.
- The older digital representations are sometimes very poor and vary enormously in terms of color. Some of these are not good photographs of book illustrations.
- The color isn’t always there either.
- The same work of art is sometimes shown lighter or darker. Here you have to do additional research to find out which one is the right one.

Fabian Felder from the University of Basel has tackled this issue in his article „A rustle in the pixel forest! Or could it be a little less yellow?“ and concludes as soon as image archives access already existing heterogeneous image databases the results are inconsistent in terms of quality especially in terms of color.
We have been aware of this problem of different colors in one and the same work from the very beginning (for over 20 years), as Lisa Dieckmann elucidates in her lecture (German only) „Mona Lisa’s sisters – on dealing with redundancies, image quality and heterogeneous metadata“ .
She presents mechanisms with which redundancies in search results can be structured in prometheus and gives an example of the advantage of redundancies: when they open up opportunities for critical reflection on images.

We will be working on additional filter and display options to deal with the mass of images in a workshop with some imaging institutions in November.

We thank everyone who filled out the “prometheus Survey 2023” questionnaire. We are pleased about the constructive criticism, the tips and wishes that we received through the comments, and we are grateful for the acceptance and appreciation.
In the next few weeks we will cluster, discuss and prioritize your statements and communicate the results here. Let’s start today with the question how you get along with the individual functions in prometheus. The results:

1 very good – 2 good – 3 so-so – 4 bad – 5 very bad – I don’t know about it

For some of these functions you also had the option to tick “I don’t know” and some of you would have preferred to indicate “I don’t use it”.
We will now take a closer look at your suggestions on how to work with the image archive in order to make the information available in other media formats (besides help, FAQ and blog) for those who are not familiar with the function.

Newly integrated into prometheus with 18,876 records is the first part of the about 50,000 glass slides of the Mediathek of the Institute for Art and Image History of the Humboldt University of Berlin.

These slides, with the monochrome photographic layer applied directly to the glass plate, were produced from the 1890s to the 1960s, used until about 1990, and digitized in 2016. Novel forms of identifying the image objects with Wikidata were tested during the area-wide acquisition, which was the focus of the project:

Last week, a few users experienced page load errors when logging in with certain browser versions. The reason was a change on our homepage. Usually we try to catch all eventualities by manual and automated tests. In case of specific error messages, however, we depend on your help to be able to fix the error. Thank you very much for your hints!

Dependencies in different operating systems, browsers and browser versions occasionally lead to problems in the agile and continuous development of prometheus. Please continue not to hesitate to actively report any technical obstacles and limitations in your work in the image archive to us. We will try to find solutions as soon as possible.

You can add your own images from excursions, museum or archive visits to your own image database (“My Uploads”) in prometheus, link them to objects, use them directly in your own image collections or share them with other users and make them available to everyone after editorial review in the sense of quality assurance on the part of the prometheus office.
In each of these image files some technical data are stored, like file size, file format, the image size in pixels and – if activated – geo references. They are read out during upload and displayed to you below the respective thumbnail. Further meta data like dating, genre or material can be added later or can be determined more precisely, like the geo references via the integrated „MapQuest“.

In the continuous maintenance and further development of prometheus, our focus is on improving your work in the image archive and thus increasing your satisfaction. To achieve this, we rely on various analyses, data and facts, as well as the use of different evaluation methods. After using structured, semi-structured and open interviews in the past, we decided to use an online questionnaire this year. This means that we now need your opinion, in which we are very interested. Many thanks in advance.

prometheus – Survey 2023
(Please note: the survey is in German but you could use e.g. DeepL or another translator of your choice. The more participants the better! We are interested in everyone’s opinion).

Also in this area we have taken the necessary measures for the security of your data, which we receive anonymously. We will inform you about the evaluation of the results and the next steps here soon.

To optimize work on the image archive, for example, when it is not available for updating, we use the analysis tool „Matomo“ in the background. When looking at the graph of the last visits to the image archive, the choice therefore fell on Friday last week, in coordination with the working hours at the computer center of the University of Cologne:

“Matomo” is an open source platform, formerly Piwik, which we have been running on our own server since mid-April. This gives us data about your usage and ensures that the data collected is not used by third parties. An overview shows us that most visits take place in Europe, and here in Germany. Now this is not surprising for us and probably not for you either. But maybe the other countries?

We will now increasingly use the anonymously detailed reports that “Matomo” provides us with about the visitors to our website and the image archive to optimize our offering.

As announced in March, you can now upload your images from your own image database, after an editorial review in terms of quality assurance by the prometheus team, for everyone in the image archive. To do this, you need to put a check mark in the editing mode of each image:

When you search for it in the database….

…you and everyone else will see the images in the result list.
For all images that you upload in the future, the check mark is already set at this point.
But of course, you can switch off the function there at any time.

After “Musée du Louvre” and “Musée d’Orsay”, the collection “Musée National D’art Moderne” of the “Réunion des Musées Nationaux – Grand Palais photo agency“, RMN for short, is now also integrated in prometheus, with 4,936 records.

Inaugurated in 1977, the Centre Pompidou is a multidisciplinary cultural institution whose collection of modern and contemporary art includes some 100,000 works from the 20th and 21st centuries.

In 1986, the national museum “Musée d’Orsay” was opened in Paris to show the great diversity of artistic creation in the Western world between 1848 and 1914. It houses national collections that come mainly from three institutions:
1. from the Louvre Museum, which houses works by artists born after 1820 or who emerged in the art world during the Second Republic,
2. from the Musée du Jeu de Paume, which has been dedicated to Impressionism since 1947, and
3. from the National Museum of Modern Art, which exclusively houses works by artists born after 1870.

With 66,434 records, these collections are integrated into prometheus as the next museum image database: “RMN Musée d’Orsay”: