By default, everything you put into the project folder will be shared publicly. This typically includes:
works by others than yourself or your co-authors, because you may use existing data, images or software. Make sure to only share those to the extent you are allowed to.
work that was created by yourself or your co-authors.
Copyright and licensing can be complicated. In this chapter, 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 the purpose of this chapter, by license we mean copyright license.
Works under a free/open license “can 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 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.
We explain below how to choose a license that brings the desired “settings”.
Can I Share the Work of Others?
To determine whether a particular work 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 for license statements include a project’s README file or a dedicated LICENSE or COPYING file. If a project has been stored in a research repository, sometimes the license is stored in the metadata of the project and displayed somewhere on the project’s page.
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.
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.
Once you found a license, you need to determine whether it is a standard (boilerplate) license and whether it is a free/open. Then you can share the reused material in your repository.
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:
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:
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 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)
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)
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.
Under Which Conditions?
Finally, if you verified that the work has been made available to you under a free/open license, you need to understand the conditions under which you are allowed to include the work in your project folder and share it with others – regardless of whether you modified it.
In the following, we will explain the most important conditions of the licenses listed above. For other licenses we recommend reading their text in full and/or consulting with a lawyer. The conditions of many popular free/open licenses are also summarized on ChooseALicense.com, which you can use to get a general idea of a license. Specifically for software licenses the Open Source Automation Development Lab provides useful checklists detailing the respective obligations.2
Note 1: Private Use
In the following, we only discuss the conditions under which works may be shared. This is because free/open licenses put no conditions on private use, where the work is not made available to others.
Attribution
Licenses may require that you provide attribution to the author(s)3 and to retain any copyright notices,4 although the specifics vary between licenses. For example, Creative Commons licenses other than CC0 require that the name of the author, the title of the work, and a link to the work are provided.
Projects with many authors often explicitly allow for an attribution to the collective as a whole rather than being mentioned individually. Software projects may use copyright notices that only contain the project name, such as Copyright (c) 2020-2025 The XYZ Project Contributors(Winslow, 2020).
Where to put the attribution depends on the type of the work, but in general it is best to keep it close to where the work is used and to provide all required information. For images, for example, this can be a small text next to the image.
Modifications of the work
If a work has been modified, some licenses may require that this is indicated (e.g., with a note “adapted from original”). Other licenses forbid that a work is modified. For example, the NoDerivatives clause of the CC-BY-ND-4.0 licenses say:
If you remix, transform, or build upon the material, you may not distribute the modified material.
Hence, in this case you are free to reuse and redistribute the material - as long as you don’t change it.
Commercial reuse
The NC clause in the Creative Commons BY-NC (Attribution–NonCommercial) license stands for “NonCommercial”, meaning that others are allowed to use, share, adapt, and build upon the work – but not for commercial purposes. This restriction prohibits any use that is primarily intended for or directed toward commercial advantage or monetary compensation. For example, using the work in an advertisement, selling it, or incorporating it into a product for sale would not be permitted without additional permission from the copyright holder. However, non-profit educational use, personal projects, or sharing within a non-commercial community is generally allowed, as long as proper attribution is given to the original creator.
Indicate License / Add License Text
Licenses may either require that one mentions the applicable license by name and possibly link (“Indicate license”) or they even require to copy the full license text along with the used work (“Add license text”).
Copyleft
If the original work has been made available under a “copyleft” license, any derivative work that is shared with others must be put under the same license as the original work5 – or you commit a copyright violation.
This explains the origin of the term copyleft, as it “turns copyright around” to make works permanently free. In the realm of Creative Commons licenses, copyleft is also called share alike (e.g. in the CC-BY-SA-4.0 license).
What is considered creation of a derivative work varies between jurisdictions, but the following are typical examples: translating a text into a different language, taking a picture of an artwork, adding a song to a video, adapting a computer program to fit own use cases, or taking a screenshot of a computer program. In all of these cases, if the original work is under a copyleft license, then sharing of the resulting derivative work is only allowed if it is put under the same license.
The question is then: Which uses of a work do not create a derivative work? In many cases, if an unaltered excerpt “is used to illuminate an idea or provide an example in another larger work” (Creative Commons, 2024a) no derivative work is made. The excerpt needs to “remain separate and distinct in the new context” (Kreutzer, 2024, p. 44) and not be “merged with other material into a new and larger work” (Kreutzer, 2024, p. 45). For example, embedding images in a document and clearly separating them from the rest or assembling works as part of a collection typically would not create a derivative work. However, due to a lack of case law, there is only little guidance on what constitutes a derivative work in general.
Also note that the copyleft licenses we discuss here do not mandate sharing. Copyleft (and attribution) clauses are only triggered if the work is shared (Creative Commons, 2015). This means that if you only use a work internally, you do not need to share your derivative works.
Tip 1: Required Information under Creative Commons Licenses
For most Creative Commons licenses, providing the following information is required (if available):
Obviously, if you are in doubt whether a condition of the license applies in your use case, it is better to either follow it or to ask the author for clarification or explicit permission.
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).
Important 1: Non-copyright Restrictions
The free/open licenses we discuss here mostly grant copyrights (with some of them explicitly granting patent rights and sui generis database rights). Therefore, you may lack other rights such as personality, privacy, moral, or trademark rights. For example, sharing photos that depict people is not only a matter of copyright, but also of privacy rights. Also, their commercial use may require the consent of the depicted person.
✍️ 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:
Under which license is the picture available?
Is it free/open?
Under which conditions may the work be shared?
Tip 2: License of Penguin Picture (Solution)
The picture has been put under the license CC0 1.0
The license is free/open
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.
Tip 3: Attribution for Penguin Picture (Solution)
Although the license CC0 doesn’t require it, we still recommend providing proper attribution.
Indicate modification: (no existing modification notices)
" 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:
" 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.
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 statusgit 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:
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
