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Choose your license

Learn more about Creative Commons licenses and pick the one that's best for your purposes

In this task we will take a look at the Creative Commons licenses and how they can help you to open up your data. If you are interested in learning even more about Creative Commons, we suggest you take the 'Get CC savvy'-course.

Creative Commons is a nonprofit organization that enables the sharing and use of creativity and knowledge through free legal tools.

The idea of universal access to research, education, and culture is made possible by the Internet, but our legal and social systems don’t always allow that idea to be realized. Copyright was created long before the emergence of the Internet, and can make it hard to legally perform actions we take for granted on the network: copy, paste, edit source, and post to the Web. The default setting of copyright law requires all of these actions to have explicit permission, granted in advance, whether you’re an artist, teacher, scientist, librarian, policymaker, or just a regular user. To achieve the vision of universal access, someone needed to provide a free, public, and standardized infrastructure that creates a balance between the reality of the Internet and the reality of copyright laws. That someone is Creative Commons.

Creative Commons developed easy-to-use copyright licenses to provide creators a simple, standardized way to give the public permission to share and use their creative work — on conditions of your choice. CC licenses let you easily change your copyright terms from the default of “all rights reserved” to “some rights reserved.” Creative Commons licenses are not an alternative to copyright. They work alongside copyright and enable you to modify your copyright terms to best suit your needs.

Building blocks

Creative Commons licenses are articulated into four basic clauses which the licensor can choose and match to his needs: 


Attribution (BY) – «You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work).» This clause is a feature in every license. It states that every time we use the work we must clearly indicate who the author is.


Non Commercial (NC) – «You may not use this work for commercial purposes.» This means that if we distribute copies of the work, we can not do it in any way which is primarily intended for or directed toward commercial advantage or private monetary compensation. To do this, we have to ask the licensor for specific permission.


No Derivatives (ND) – «You may not alter, transform, or build upon this work.» If we want to modify, to correct, to translate or to remix the work, we have to ask the licensor for specific permission.


Share Alike (SA) – «If you alter, transform, or build upon this work, you may distribute the resulting work only under the same or similar license to this one.» This clause - as in the Free Software model - grants that the “freedoms” conceded by the author will be also kept on the derivative works and on the derivative ones of the derivative ones, with a persistent effect.

By combining these 4 building blocks you get the 6 possible Creative Commons-licenses. We'll walk you through them, but first you need to know that there are two essential conditions for the licenses:

- The “Attribution” clause is present in every license;

‐ The “No Derivatives” clause and the “Share Alike” clause are incompatible with each other. In fact, the first one denies the modification of the work, while the second implicitly gives permission to modify the work.


With the four building blocks you can build six licences. You can find a more detailed explanation about each license on the Creative Commons site. You can also click the icons below to go straight to the license deed. The license deed is a summary of the conditions of the license in easy to understand wording. The license deed also allows you to click through to the legal code of the license if you are feeling comfortable with some legalese. 

by        Attribution

by-sa        Attribution -Share Alike

by-nd        Attribution - No Derivatives

by-nc        Attribution - Non Commercial

by-nc-sa        Attributions - Non Commercial - Share Alike

by-nc-nd        Attribution - Non Commercial - No Derivatives

Other tools

CC0 is another project by Creative Commons: it is a tool (not a license!) that allows creators to effectively place their works in the public domain through a waiver of all copyright to the extent permitted by law.


CC0 enables scientists, educators, artists and other creators and owners of copyright‐protected content to waive copyright interests in their works and thereby place them as completely as possible in the public domain, in order for others to freely build on, enhance and reuse the works for any purposes without restriction under copyright.

In contrast to CC’s licenses that allow copyright holders to choose from a range of permissions while retaining their copyright, CC0 empowers another choice altogether – the choice to opt out of copyright and the exclusive rights it automatically grants to creators – the “no rights reserved” alternative to our licenses.

In effect, we know that copyright and other laws throughout the world automatically extend copyright protection to works of authorship and databases, whether the author or creator wants those rights or not. CC0 gives people who want to give up those rights a way to do so, to the fullest extent allowed by law. Once the creator or a subsequent owner of a work applies CC0 to a work, the work is no longer his or hers in any meaningful legal sense. Anyone can then use the work in any way and for any purpose, including commercial purposes, subject to rights others may have in the work or how the work is used. Think of CC0 as the “no rights reserved” option.

The last tool we would like to present you is the Public Domain Mark

public domain mark

The Public Domain Mark enables works that are no longer restricted by copyright to be marked as such in a standard and simple way, making them easily discoverable and available to others. Many cultural heritage institutions including museums, libraries and similar  organsations are knowledgeable about the copyright status of paintings, books and manuscripts, photographs and other works in their collections, many of which are old and no longer under copyright. The Public Domain Mark operates as a tag or a label, allowing institutions like those and others with such knowledge to communicate that a work is no longer restricted by copyright and can be freely used by others. The mark can also be an important source of information, allowing others to verify a work’s copyright status and learn more about the work.

License Hierarchy

 no rights reserved





some rights reserved



all rights reserved

The figure above shows all licenses and their respective place in the spectrum between no rights reserved and traditional copyright's all rights reserved. To be Free Culture Data we only allow the use of licenses up to Attribution-ShareAlike to safeguard maximum reuse potential. 

Now it's time to choose a license a license for your data. The 'Get CC Savvy-course' on P2PU has dedicated a task to choose the right license for the job, take a look there if you want. These are our recommendations:  For metadata we recommend using CC0. Most copyright regimes do not give protection to factual data, CC0 ensures that no party can claim copyright on metadata. For content you can choose between CC0, PDM, CC BY or CC BY-SA. This way, you'll be sure that you are in line with the Free Cultural Works definition. Make sure that you have all the rights or permissions to apply the license that you want. For more detailed information about correctly applying a CC license you can also read the excellent Creative Commons user guide of Simone Aliprandi.

There are a lot of cultural institutions already working with Creative Commons licenses. If you want to know, which ones they use, u can have a look at this overview.

Once you figured out what you want, go to and generate the code for the license of your choosing. 


Please share below what license you decided to choose and why. What do you hope to achieve by using this license and what do you hope to prevent.  Take a moment to go back to what you wrote down in the first task. What kind of results would you like to achieve with opening up your data? What kind of license would enable these results and how? 

Also let us know, if somethings are still unclear, or if you've run into some kind of problem/ dilemma while choosing your license. 

Task Discussion

  • LaurenB said:

    We'll likely use a combination of CC0, CC PD, and probably CC BY SA, but probably applied only to lower resolution versions of images for the web. At first, I imagine various entities at the institution will be worried about allowing our high res images to be so open. I might be able to convince people to license the high res as CC BY ND. Eventually, I hope we'll be able to open up our high res images as BY SA as well.

    I like the idea of the CC BY SA license because of the "you scratch my back, I'll scratch yours" principle. If we're offering our data up for free and you're using it, I want you to be making it open as well.

    These licenses will allow us to upload our assets to various Wikis (as Wikipedia only allows CC0, CC BY and CC BY SA licenses), as well as contribute data to various aggregators.

    on March 26, 2013, 12:52 p.m.

    Maarten Zeinstra said:

    Hi Lauren,

    I would make a separation between how you want to license your metadata and how you want to license your content.

    Metadata is in most cases not copyright protected and is in a sense Public Domain. I would recommend using CC0 on that data. This is because some parts of the world do have some form of proterction on these sets (like database rights in Europe).

    License content according to the liberty you have within your institution. Here I always say to cultural institution that the copyrights of a analog work is the same as in the digital work. Say I digitise a 20th century painting I bought 20 years back I can probably not claim that the work is in the Public Domain, the creator is probably not dead long enough. I also don't know if I can license the work under a Creaitve Commons license. It could be the case that my institution never purchased the copyright together with the physical work. I need to check this for each work I digitise. 

    You are right in the way Wikipedia works, they only accepts these very open licenses. But don't make the mistake to publish high resolution under a more restrictive license than a lower resolution work. According to most copyright laws these works are to be considered the same! This means that the more open license of the lower resolution work can also apply to the high resolution works. Instead I would argue that you shouldn't publish these works at all and sell the high resolutuon works with a contract stating that 3rd parties can only use those images for one publication/non-commercial purposes only. In that case contract law will trump copyright law.

    Hope these extra tips are useful for you.


    Maarten Zeinstra

    on March 26, 2013, 1:09 p.m. in reply to LaurenB

    LaurenB said:

    Thanks Maarten. I appreciate your clarification. We'll definitely use CC0 on our metadata. That wasn't at all clear in the way I worded my comment, sorry about that! The vast majority of our collection here (we're talking like 98%) is pre-1850 works, both 2D and 3D, created outside of the US by non-US makers. I'd double check the rights on the 2d works, but again, I believe the vast majority of them should be public domain at this point, correct? And therefore the content associated with them should also be PD, correct? Kind of a related questions, do books count as 2D or 3D in this framework? And, to confirm, you're saying don't openly publish the high res works under a CC license if I want to "control" the use of the high res image. Instead, create a separate contract for use of those high res images (that could in theory only be obtained by contacting the institution.) Thanks again for your help! Lauren --------------------------------------------------------------------- Lauren Boegen Digital Collections Manager Webster Institute for the History of Astronomy The Adler Planetarium and Astronomy Museum phone: 312.542.2618 mzeinstra <
    on March 26, 2013, 1:28 p.m. in reply to Maarten Zeinstra

    Maarten Zeinstra said:

    Just happy to see the course is in use. :)

    Again, I am no law scholar and these laws can vary per jurisdiction. 

    I consider everything that was created prior to 1860 as public domain. I use the rule of thumb that everything created after 1942 is still copyright protect. Copyright protection is generally january 1st 70 years after the death of the author and 1942 is 70 years ago. I about 80 years to be on the safe side. We can assume that almost all people who created works in 1860 died before 1942 and can therefore considered as PD. Again this is a rule of thumb, the actual year that a work enters the PD varies.

    Now when you create a 2D digital reproduction of a 2D work then the copyrights are the same in both objects. Remember that you are making a copy. 

    3D works however are different. Do you consider a 3D scan of a work a 'reproduction'? If so than you can claim that the rights of the analog work can also be claimed in the digital work. If you cannot claim that this is a reproduction than you could possibly be talking about a new work with new rights. In that last case you will need to look at the contracts that you made with the people who created these works. Do you allow you to publish them under open licenses?

    Regarding the jurisdiction where these works are created. It does not matter where these are created, it matters where you seek protection. For example Mexico has the longest copyright protection in the world (100 years after the death of the author), most of Europe has 70 years after the death of the author. That means that I could legally use a work as it was in the Public Domain 30 years earlier in Europe before it could be used in Mexico. See:

    Again, I'm not very versed in the duration of copyright protection in the US, go to this site for some assistance on the copyright status in the USA

    on March 26, 2013, 5:48 p.m. in reply to LaurenB