Sharing work of others: Copyright

By default, everything you put into the project folder will be shared publicly. This typically includes:

When sharing works by others, you need to make sure that you are allowed to do so, which is the topic of this chapter. As copyright and licensing can be complicated, we focus on rather simple (but typical) situations. For an in-depth explanation of copyright and licenses, see our supplementary in-depth material “Introduction to Copyright and Licenses”.

Short Introduction to Copyright and Licenses

Whenever authors create a literary or artistic work (such as a text, image, video, or software), the copyright law1 in most countries limits other people from copying, modifying, and sharing it without the author’s express permission. Copyright licenses enable authors to free up their works for reuse by others.

A license is a legal document that regulates what other people than the author can and cannot do with a copyright-protected work, and under which conditions. We strongly recommend to use existing boilerplate licenses (and not to craft your own license text). For example, you might have heard about “Creative Commons” licenses, which are used by Wikipedia.

For the purpose of this tutorial, by license we mean copyright license.

In particular, we recommend reusing works under a free/open license, which allow the work to “be freely studied, applied, copied and/or modified, by anyone, for any purpose” (Möller et al., 2015). Importantly, this also means that others do not need to ask or notify the author and that they can use it also for commercial purposes. If you modified the work and put a sufficient amount of creativity into it, the result is called a derivative work.

Even for free/open licenses, authors can place certain demands on re-users of their material. For example, they can (optionally)…

  • demand that they are credited as the creators of a work,
  • that the original license must be indicated when a work is reused,
  • that modifications are indicated,
  • that derivative works are only shared under the same license, or
  • that no further restrictions are imposed on the derivative work.

When Can I Share the Work of Others?

To determine whether a particular work of others can be included in the project folder and shared publicly, the first step is to search for its license. For example, this tutorial has an About page detailing its licensing, whereas other websites sometimes state the license in the footer.

Other places to look include a project’s README file or a dedicated LICENSE or COPYING file. If a project has been stored in a research repository, yet another means of communicating its copyright status might exist. For media from Wikimedia Commons, you can determine the license using the website lizenzhinweisgenerator.de.

If you cannot find any license, the work might be in the public domain (see details here). In this case, you can simply reuse it, but still should credit the original creator(s) in accordance with good scientific practice.

If no license notice is present and the work is not in the public domain, it is by default in copyright and you are generally not allowed to share it with others. You can, however, ask the author to put the corresponding work under a free/open license – Wikimedia Commons provides an email template to obtain such a permission.

Without permission you can check your national laws for limitations and exceptions to copyright.2 Examples include the right to quote, trivial use, scientific research exceptions, and the US-American fair use.

Once you found a license, you need to determine (1) whether it is a standard (boilerplate) license, (2) whether it is a free/open, and (3) whether it is appropriate for the particular type of work and use case.

Below are listed several standard free/open licenses. To better understand the conditions under which you are allowed to include others’ works in your project folder, please take a look at our supplementary Copyright Conditions page.

For a software license to be considered free/open, it must be approved by either the Open Source Initiative (OSI) or the Free Software Foundation (FSF). Some of the most common free/open software licenses are listed below:

  • GNU Affero General Public License v3.0 (AGPL-3.0)

    You can share under these conditions:

    • Attribution
    • Add license text
    • State changes
    • Disclose code
    • Strong copyleft

    Link to full text

  • GNU General Public License v3.0 (GPL-3.0)

    You can share under these conditions:

    • Attribution
    • Add license text
    • State changes
    • Disclose code
    • Strong copyleft

    Link to full text

  • GNU Lesser General Public License v3.0 (LGPL-3.0)

    You can share under these conditions:

    • Attribution
    • Add license text
    • State changes
    • Disclose code
    • Weak copyleft

    Link to full text

  • Apache License 2.0 (Apache-2.0)

    You can share under these conditions:

    • Attribution
    • Add license text
    • State changes

    Link to full text

  • Mozilla Public License 2.0 (MPL-2.0)

    You can share under these conditions:

    • Attribution
    • Indicate license
    • Disclose code
    • Weak copyleft

    Link to full text

  • MIT License (MIT)

    You can share under these conditions:

    • Attribution
    • Add license text

    Link to full text

  • BSD 3-Clause “New” or “Revised” License (BSD-3-Clause)

    You can share under these conditions:

    • Attribution
    • Add license text

    Link to full text

  • BSD 2-Clause “Simplified” License (BSD-2-Clause)

    You can share under these conditions:

    • Attribution
    • Add license text

    Link to full text

If you did not find a particular software license in this list and consult the resources by the OSI and/or FSF linked above, be cautious because they also approve special-purpose licenses that are unfit for software in the general case. For example, the license CC0 1.0 expressively does not grant patent rights and one should only use software under that license if it is most likely not covered by patents.

Many authors of text and media put their work under a license created by Creative Commons. Not all Creative Commons licenses are free/open, however, as some of them prohibit commercial use or the distribution of modified works (such as sharing a translated version). Therefore, we recommend to only use works made available to you under CC0 or under Creative Commons licenses with the modules “Attribution” (BY) or “ShareAlike” (SA), but without the modules “NonCommercial” (NC) and “NoDerivatives” (ND). In their most recent version this includes the following licenses:

  • CC0 1.0 (CC0-1.0)

    You can share under these conditions: (none)

    Link to full text

  • Creative Commons Attribution 4.0 (CC BY 4.0)

    You can share under these conditions:

    • Attribution
    • Indicate license
    • State changes
    • Anti-DRM

    Link to full text

  • Creative Commons Attribution-ShareAlike 4.0 (CC BY-SA 4.0`)

    You can share under these conditions:

    • Attribution
    • Indicate license
    • State changes
    • Anti-DRM
    • Copyleft

    Link to full text

Of course, if you encounter a Creative Commons license with a previous version that satisfies the description above, it can be also considered free/open. If you encounter a license not from Creative Commons and want to determine whether it is free/open, you can consult the lists of licenses accepted at Wikimedia Commons. Note, however, that some of the licenses there might be inappropriate for text and media. For example, licenses for software or for documentation commonly require to distribute a work together with the full license text, which is impractical for usage in print media.

Purely factual data such as measurements are usually not copyrightable, but literary or artistic works that cross the threshold of originality are. Additionally, in some jurisdictions, collections of data (i.e., databases) can be subject to sui generis database rights which prevent extracting substantial parts of a database.

As a consequence, a database may be licensed differently than its content. For example, with a database of artworks, the artworks may be licensed individually as chosen by the artists, but the license for the database as a whole might have been chosen by the curator, including the selection of entries, field names and any sui generis database rights. Watch out for any signs that the license for the database and its content are not the same. In the following, we list some popular free/open data licenses:

Note: The listed conditions are the major conditions for sharing (there might be additional conditions defined in the license).

  • CC0 1.0 (CC0-1.0)

    You can share under these conditions: (none)

    Link to full text

  • Creative Commons Attribution 4.0 (CC BY 4.0)

    You can share under these conditions:

    • Attribution
    • Indicate license
    • State changes
    • Anti-DRM

    Link to full text

  • Creative Commons Attribution-ShareAlike 4.0 (CC BY-SA 4.0)

    You can share under these conditions:

    • Attribution
    • Indicate license
    • State changes
    • Anti-DRM
    • Copyleft

    Link to full text

Note that Creative Commons licenses prior to version 4.0 are not suitable for databases. You might also encounter the following, less popular free/open data licenses:

  • Open Data Commons Public Domain Dedication & License 1.0 (PDDL-1.0)

    You can share under these conditions: (none)

    Link to full text

  • Community Data License Agreement Permissive 2.0 (CDLA-Permissive-2.0)

    You can share under these conditions:

    • Add license text

    Link to full text

  • Community Data License Agreement Permissive 1.0 (CDLA-Permissive-1.0)

    You can share under these conditions:

    • Attribution
    • Indicate license

    Link to full text

  • Community Data License Agreement Sharing 1.0 (CDLA-Sharing-1.0)

    You can share under these conditions:

    • Attribution
    • Indicate license
    • State changes
    • Copyleft

    Link to full text

Finally, you should know about the following two free/open licenses because they only cover the database, but not its individual contents or the works produced from it. If any of these licenses is used, the license for the content must be stated separately.

  • Open Data Commons Open Database License v1.0 (ODbL-1.0)

    You can share under these conditions:

    • Attribution
    • Indicate license
    • Anti-DRM
    • Copyleft

    Link to full text

  • Open Data Commons Attribution License v1.0 (ODC-By-1.0)

    You can share under these conditions:

    • Attribution
    • Indicate license

    Link to full text

If you encounter a license not listed here and want to determine whether it is free/open, you can consult the lists of licenses accepted at Wikimedia Commons. Note, however, that some of the licenses there might be inappropriate for data, because they do not mention sui generis database rights.

Tip 1: Required Information under Creative Commons Licenses

For most Creative Commons licenses, providing the following information is required (if available):

We recommend that you always provide attribution for all works under a free/open license – even if the license does not strictly require it (e.g., CC0). This also follows from the rules of good scientific practice (and not only from copyright law).

Practical Exercise: Adding an Image

Let’s practice what you learned by adding an image to the manuscript. We’ll use this picture of a penguin from Flickr. First, try to answer the following questions:

  1. Under which license is the picture available?
  2. Is it free/open?
  3. Under which conditions may the work be shared?
  1. The picture has been put under the license CC0 1.0
  2. The license is free/open
  3. The license contains no (major) conditions

You can now download the image and move it to your project folder (maybe call it penguin.jpg). In your manuscript file, find the line that says “add image here”, remove it, and add the image instead, including proper attribution.

Although the license CC0 doesn’t require it, we still recommend providing proper attribution.

!["[Chinstrap Penguin](https://flic.kr/p/2pEKnUr)" by "steve b" licensed under [CC0\ 1.0](https://creativecommons.org/publicdomain/zero/1.0/)](penguin.jpg){width=50%}

If it is likely that the article gets printed, you might want to ensure that the link to the work is retained in that case:

!["[Chinstrap Penguin](https://flic.kr/p/2pEKnUr)" by "steve b" available under [CC0\ 1.0](https://creativecommons.org/publicdomain/zero/1.0/) from [`flic.kr/p/2pEKnUr`](https://flic.kr/p/2pEKnUr)](penguin.jpg){width=50%}

Let’s render the document and see if the changes were successful (open Manuscript.pdf afterwards):

Terminal
quarto render Manuscript.qmd

In addition, we recommend creating a file called LICENSE.txt to describe the license of the image. Click on File > New File > Text File, then on File > Save, and choose LICENSE.txt as filename. The license description can be worded as follows:

LICENSE.txt
"Chinstrap Penguin" stored in "penguin.jpg" by "steve b" available from <https://flic.kr/p/2pEKnUr> is licensed under CC0\ 1.0: <https://creativecommons.org/publicdomain/zero/1.0/>

If the license required adding the full license text, you would also need to copy it to the project folder.

Finally, you can store the changes in the version control system:

Terminal
git status
git add .
git commit -m "Add image"

Wrap-up

If you would like to learn more about copyright and licenses you might find the following resources interesting:

  • Our own in-depth material on copyright and licenses (which is an extension of this chapter)
  • “Open Content – Navigating Creative Commons Licenses” by Kreutzer (2024)
  • “Creative Commons Certificate for Educators, Academic Librarians, and Open Culture” by Creative Commons (2024)
  • “Freie Software – Zwischen Privat- und Gemeineigentum” by Grassmuck (2004)
  • “Rechtsfragen bei Open Science: Ein Leitfaden” by Kreutzer & Lahmann (2021)
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References

Creative Commons. (2024). Creative Commons certificate for educators, academic librarians, and open culture. https://certificates.creativecommons.org/cccertedu/
Grassmuck, V. (2004). Freie Software: zwischen Privat- und Gemeineigentum (2., korrigierte Aufl). Bundeszentrale für politische Bildung. https://web.archive.org/web/20240105071919/https://freie-software.bpb.de/
Kreutzer, T. (2024). Open content – navigating Creative Commons licenses. Deutsche UNESCO-Kommission e. V. und Wikimedia Deutschland - Gesellschaft zur Förderung Freien Wissens e. V. https://www.unesco.de/assets/dokumente/Kommunikation/01_Kommunikation_allgemein/Open-Content_Dez_2024.pdf
Kreutzer, T., & Lahmann, H. (2021). Rechtsfragen bei Open Science: Ein Leitfaden. Hamburg University Press. https://doi.org/10.15460/HUP.211
Möller, E., Hill, B. M., Garlick, M., Stark, E., Knapp, J. A., Kadlec, P., Stallman, R., Lessig, L., & Beesley, A. (2015, February 17). Definition of free cultural works. https://freedomdefined.org/Definition/1.1

Footnotes

  1. in Germany: Urheberrecht↩︎

  2. in Germany: Schranken des Urheberrechts↩︎