Fotopedia – the rating system (1/2)

Last modification: 2-Oct-10

Fotopedia‘s system for ranking the quality and suitability of photos is is based on counting votes. This results in cumulative ratings like +2 (few people have seen the image, or maybe people don’t like it) , +22 (a more popular image), or -2 (some people care enough to vote it down). Fotopedia’s rating system has multiple purposes:

  1. It helps remove less interesting or less relevant photos.
  2. It results in a ranking among the stronger photos (e.g. to view the “best” ones).
  3. It helps motivate the photographers.

If the system for rating and ranking works well, users looking for information find great photos. If it works well, photographers and rankers also stay motivated and keep contributing their photos and energy. A good ranking system should thus help Fotopedia outperform alternative and more straightforward ways (e.g. Flickr, Google) when you are interesting in high quality photos that illustrate a particular subject.

Ratings (e.g. +1) are valid in the context of an article ("Black cat").

Purpose of this posting

Fotopedia plans to update their rating/ranking/voting system. This posting analyzes the “old” ranking system, presents some general ideas for improvements, and hopes to trigger some good discussion on the topic. The second part of this posting becomes a bit more concrete about what an improved rating and ranking system could look like.

Learning from the search engines

Search engines such as Google face a similar challenge: they need to present the most relevant Internet pages for a search query at the top of the list of results. This helps the user find results quickly.

Initially such page ranking algorithms selected pages based on keyword matching: if you search for apple boot camp you would find pages which contain all 3 words. But particularly Google excels in guessing a page’s relevance by looking at the other pages that link to that page. Google’s proprietary PageRank algorithm uses the estimated ratings of linking pages to rank the linked page. The assumption is that if a page is interesting, other page will link to it. And if a page is really interesting, other interesting pages will link to it.

So Google essentially uses information that is automatically harvested from the Internet to guess which pages fit your search best. Note that this means that there is no need for people to answer questions about the pages in order to find out which ones are good. The entire system is thus automated (albeit with the use of vast compute resources).

Fotopedia’s challenge is different: if you are looking for photos of Grapes, the software requires humans to link photos to the Grape article. And the software needs additional human help to judge the quality and relevance of the submission.

Despite differences between searching for text and searching for photos, we can still learn something from the search engines:

  1. Ranking algorithm accuracy is critical: Google kept competition (remember AltaVista?) at bay largely by using smarter ranking algorithms.
  2. You might be able to get hints about photo quality/relevance by using available data in a smarter way. It is OK for the ranking system to be a bit fancy, and the exact method of scoring doesn’t need to be visible to the users – it is only important that users see enough of the ranking system to know that their votes make a difference and to believe that the system is fair.

And obviously, the quality of the questions which are asked to users about photos are critical in determining how much you can learn about the suitability of the photos and how long it takes the system to learn what it can learn. Both points (learning the right things, and learning them with as little user input as possible) are areas that could be improved.

The “old” Fotopedia rating system

A user can vote once on any photo (per article in which it is used). Giving it a “thumbs up”. adds +1 to the score or rating of the photo. Alternatively “thumbs down” decreases the rating by 1. Actually the rating only applies to that photo in the context of one specific article – even though the photo may be linked to multiple articles.

My photo of the violin of a famous 19th century Norwegian violinist scored +5 for the article on the violinist, it also rated +5 for the article about the violin’s builder, but it received a -1 rating as a general picture of a violin.

Scores of +5 or more (counting the original poster) currently promote an image from Candidate to Top, meaning that it becomes an official photo for that article. Enough subsequent thumbs-downs can kick the photo out of the list of Top photos. The threshold between Candidate and Top is sometimes manually set by Fotopedia staff to higher values like +10 when there are numerous  submissions (e.g. Flower has 300 submissions).

This photo was linked to the violinist, the violin maker and to Violin.
powered by Fotopedia

Moderators are empowered to give larger rating boosts – mainly to shorten the learning process (which can now take months or years). I am not aware that moderators (can) reduce the score of a photo by more than one. But they can undo the link between a photo and an article if the photo is unsuitable or has had a negative score for a long time.

A smarter ranking algorithm needed

Unlike Google, Fotopedia currently does its ranking using very simple algorithms on manually provided information. Currently a user only has two ways to influence a photo’s rating and ranking:

  1. increase the rating by one
  2. decrease the rating by one

That means everybody (except for moderators?) has the same impact – regardless of their track record or qualifications. Examples of information that is not used:

  • is the +1/-1 choice because of visual- or content reasons?
  • how knowledgeable is the photographer/submitter? (e.g. New Yorker supplying a New York photo)
  • how knowledgeable is the voter? (e.g. New Yorker voting on a New York photo)
  • say a photo is linked to both the “Gondala” and the “Venice” articles. If the photo is rated in one context, the rating in the second context is unchanged.
  • is the photo better/worse/similar to existing photos in the set?
  • is the photo exceptional, excellent, good, average, etc. according to the voter?

What kind of photos should rank high?

It helps to be explicit (and agree) on what we are trying to measure and what we are trying to achieve with the measurement.

The question current asked to a voter is:

“Is this a great photo to illustrate this article?”

This helps, but doesn’t tell us whether we are looking for great-looking photo that is somehow relevant for the article, or a photo that adds significant information to the article but may not be visually great. So I believe it is important to answer whether Fotopedia is mainly aims to be

  • a reliable source of information and show interesting aspects of the topic (goal is to be an “encyclopedia”),
  • a source of visually pleasing pictures showing the subject and showing it in an interesting way (goal is to be a series of “coffee table books”), or
  • both of these at the same time?

The Quality Chart currently says:

The world isn’t perfect. You might feel the need to represent it differently using Photoshop and your artistic talent. The encyclopedia isn’t the place to express such needs. We illustrate the world as it is, in all its beauty and ugliness. Artistic and overprocessed photos (including HDR) don’t belong.

Although this may suggest that Fotopedia images should be first and foremost informative, Fotopedia’s derivative iPad applications like “Heritage” rely heavily on the visual side. The current lack of emphasis on captions and the set of article links when rating a photo also suggest that the visual side is currently getting more attention.

Salon, library or both?

My assumption in the in the rest of this discussion piece is that an ideal Fotopedia photo should be both informative and visually pleasing – although I can’t define either precisely. This means that Fotopedia would target both the salon’s coffee table and the library’s bookshelf – so to speak.

The photo is linked to the Lighthouse article and is visually pleasing. It clearly illustrates what a lighthouse is and does, but information about location is missing.
powered by Fotopedia.

The “informative” and information accuracy are needed if Fotopedia aims to serve as a visual wrapper around- or companion to Wikipedia. But I believe “attractive” is also needed because:

  1. Even newspapers select photos (“President holding speech”) on both criteria. Newspapers are commercial products and readers prefer newspapers with “nice” pictures. The same applies to Fotopedia.
  2. Fotopedia plans to use its image collection to publish more “coffee table books” (like Fotopedia Heritage for the iPad). By definition, coffee table books should attract casual browsing and depend heavily on picture and graphical design quality.
  3. The vast majority of Fotopedia photos are already visually attractive. In fact, I wouldn’t be surprised if many voters decide to vote +1 mainly when the picture is nice (e.g. “good enough to hang on the wall”) and on-topic – but in that order!
  4. The rating is critical to motivate photographers to submit images. The rating system shouldn’t be too different from how photographers and their customers (editors, clubs, relatives) rate images – especially for documentary images. A photographer (e.g. for National Geographic) will strive to support the article’s text with attractive pictures.

A final example

An example of emphasis on aesthetics without worrying about the encyclopedia goals are a series of photos of fruit being dropped into water. This gives visually interesting photos and this photo actually earned the highest ranking within the Grape article. I would say it is clearly less suitable as an encyclopedia photo because the water and the splashing don’t convey anything relevant: it doesn’t tell me about grapes, how they are grown or how they are used. So ranking suggests that people often rate pictures on their photographic merits, while ignoring the informational merits.

A visually attractive and technically challenging photo, but unsuited to illustrate grapes.
powered by Fotopedia

[ see continuation in part 2 of this article ]

This entry was posted in Fotopedia, Information Technology and tagged , , , . Bookmark the permalink.

7 Responses to Fotopedia – the rating system (1/2)

  1. Chris Wells says:

    Hi Peter:

    This is a really great article. It is clear, thoughtful, balanced and sensitive to the needs of photographers. There is really no recommendation in the article that I don’t agree with.

    The article covers a lot of territory and will, I am sure, lead to a lot of discussion. I hope it also leads to some action.

    I am not a software programming expert and I don’t really understand many of the features of Fotopedia ranking or “authority” (how and who gets to “beat the system” is very non-transparent in the Fotopedia world). I suspect that, like many creative environments, the founders have their prerogatives and the rest of us will need to live with them. Personally, I continue to be inspired by the concept of Fotopedia and would like to work on making my humble contributions for the time being trusting to others (including you) to figure out how make the environment better.

    I think it would be very helpful as a follow up to the above recommendation set if you could prioritize the recommendations. The priority might be set on the basis of “ease of implementation” rather than “level of environmental improvement”. I suspect that some of the recommendations could be done in a short time, while others are likely to be more controversial and require some debate.

    Nevertheless, personally it would be helpful to my understanding if you could outline a “practical roadmap” for implementation of the recommendations.

    I very much like the idea of giving photos where the photographer has bothered to explain the relevance of the photograph to the topic some priority. I think there is also a need for enhancing dialogues between persons rating a photo on “I” and the photographer. We don’t want raters and photographers to be “flaming” at each other, but it would be helpful if we could make comments that might pop-up in a scroll-over window when someone is rating the photos.

    I think the idea of having a hierarchy for curators (I don’t even know how to become qualified for this role) is a good idea. Perhaps we can use something like “Novice, Journeyman”, “Master” and “Grandmaster” for this.

    In any event, I just want to thank you for taking the time to write such a comprehensive, thoughtful and helpful article. Fotopedia is very lucky to have people of your commitment and thoughtfulness working on the project.

    Best regards,


    • pvdhamer says:

      if you could prioritize the recommendations. The priority might be set on the basis of “ease of implementation”

      Sounds sensible. Obviously, in order to get a roadmap, we need some general agreement of priorities and direction. And, as you noted, Fotopedia’s staff “have their prerogatives”. Unlike Wikipedia, they are a commercial company. I obviously have to see how well they take my “meddling” in their affairs and they will have to see if my inputs are useful. On the optimistic side, I know that they are soliciting opinions from active people in the community and I was encouraged to approach a few people like yourself for feedback.

    • pvdhamer says:

      [..] like the idea of giving photos where the photographer has bothered to explain the relevance of the photograph to the topic some priority. [..] need for enhancing dialogues between persons rating a photo on “I”[nfo content] and the photographer. [..] helpful if we could make comments that might pop-up in a scroll-over window when someone is rating the photos.

      I agree that FP should enable such dialog more. To start, I would show captions (=text supplied with the photo and that stays available to document the photo) before ranking, and maybe show captions while browsing. A dialogue channel about a photo is also badly needed. But for the informational side, you may first need a baseline text – separate from discussion text – to discuss. Wikipedia also distinguishes Article and Discussion tabs. FP should keep both separate as well. My roadmap tip (smiley) would be to get a stable caption concept, and (lower priority) a dialogue “page” per photo where discussions about discussion related to or directly triggered by the photo are valid. Just like comments in a blog: “I rated you low because…”, “is that Japanese bowl from your own collection?”. I suspect FP already has thought about such discussion pages.

      Back to captions: Fotopedia still has a bit of an identify problem in choosing whether it belongs in the Library (, or in the Salon (Heritage, National Geographic). I believe they can and should pull off both. In fact, this is for me the genius of Fotopedia: if they manage to pull off being both, they get both the cerebral and aesthetic communities as users and as contributors. Their struggle with captions (something like “encode what the photo is about in article links, put the story of how this picture was made in the caption”) illustrates where FP clearly choose for Salon rather than Library.

      There is a catch, however, as soon as you get serious on captions (I think FP also figured this out, given their guideline on captions): Try displaying Fotopedia images and Wikipedia text on the same screen. Do the captions need to be just as reliable as the Wikipedia text: sources, footnotes, 3rd party corrections? If I say “this cartouche is that of Pharaoh Ramsesses II”, this is useful, but it could be wrong. The same obviously applies to associations (to Ramesses II article), but a caption can contain much more info.

  2. Adrian says:

    Another issue with captions is that that they are in one language. Photos are international, everyone can enjoy them. Text is more difficult. We are working on a multilingual version of Fotopedia and the fantastic work done at Wikipedia, which has translations in many languages, enables us to offer relevant text in several languages. Captions can’t be so universal.

    It is the same with the rating system. Comments are in one language, but a thumbs up or down or another form of rating is universal. The “report inappropriate” feature enables you to comment on a photo, yet we have structured it in a way that will enable us to translate it and still give meaningful feedback (structure which can be expanded of course). [bold added by PvdH]

    • pvdhamer says:

      Multilingual versions of Fotopedia sound nice. This gives readers a choice of language (automates an extra click in Wikipedia). Hopefully it also allows photographers to post on Wikipedia articles that only exist in non-English versions of Wikipedia.

      Note that English/French/Spanish/… versions of Wikipedia are normally not translations of each other. They are more or less independently written articles on the same subjects. This actually strengthens the need for captions as I can only assume the most basic information is present in all available languages.

      So, we still need a solution for captions like this one where the caption is essential to understand what you are seeing. This is important if FP wants to cater not just to the coffee table users, but also to encyclopedia users. For now I would just provide the caption, while capturing its language (a motivated reader can always use an online translator to decode it). And later FP could allow “authors” to provide their caption in multiple languages if the author is motivated: a Danish poster on a Danish topic should be encouraged (but not forced) to write in English, but can then also provide a Danish version (or Swedish or German…).

      Multi-lingual support in comments would be a much lower priority for me: the people involved tend to figure out what works and what doesn’t. The problem applies to any other forum.

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