An open license, also called free license, in the context of digital content, concedes a set of conditions to an original work that grants permission for anyone to make use, modify and distribute, that work as long as they follow the conditions of the license.
These licenses can be used to share knowledge, data, or creative works.
This post is an introduction to free and open licenses.
General-purpose Open Content Licenses
Open content licenses are general-purpose open licenses that may be applied to text, graphics, music, sounds or artwork.
An example of general open content license are the Creative Commons family of licenses.
You can find a list of general open content licenses on this post.
In the case of software, the Free Software Foundation (FSF) does not recommend to use a Creative Commons license to license software (except when using CC0) and suggests instead to use other software-specific equivalent licenses. These licenses are explained in the corresponding section.
Open Licenses specific to types of Works
There are free and open source licenses specific for some types of works, like for example:
- Software
- Data
- Images
- Documentation
- Images
- Artwork
Take into account that all the previous
It is recommended that you use a license that suits the type of work you want to protect.
Open-Source Software Licenses
Free and Open-Source Software (FOSS) licenses allow to use and distribute software under certain conditions, while ensuring that the software still follows the definitions of free and open-source.
You can check a detailed post about FOSS licenses on this post.
Open Data Licenses
There are some open licenses specific to databases.
You can find a list of open data licenses on this post.
Open Image Licenses
Open images usually use a general open content license, such as the open Creative Commons licenses (CC0, CC-BY, CC-BY-SA).
To mark open images as such, the images are usually accompanied by a text caption that informs about its license.
Additionally or in the cases where no text caption is possible (for example, in graphics used in a video game), you can embed licensing metadata into certain kinds of image files.
You can read how to embed metadata to a image file on this post.
Open Documentation Licenses
An example of open documentation license would be GNU Free Documentation license. The documentation that goes with GNU software documentation uses this license.
General open content licenses, like the Creative Commons licenses, are also commonly used for documentation.
Open Artwork Licenses
There are different open licenses specific for artwork. Take into account that artwork could also be licensed using the more general open content licenses.
One of the most prominent open artwork license is Free Art License (FAL), whose latest version is FAL 1.3. It is legally compatible with CC BY-SA 4.0.
Organizations supporting Open Licenses
There are some international organizations that support and promote open licenses.
Creative Commons
Creative Commons is an American non-profit organization.
Open Knowledge Foundation
Open Knowledge Foundation (OKF), temporarily known as Open Knowledge International is a global, non-profit network that promotes and shares information at no charge, including both content and data.
Free Knowledge Foundation
Free Knowledge Foundation (FKF) is associated with the Free Software Foundation Europe.
Definition of free and open Licenses
The Open Definition
The Open Definition is defined by the OKF.
The Definition of Free and Cultural Works
The Definition of Free and Cultural Works is defined by Creative Commons and other relevant people and organizations.
Books supporting open Content
- Lawrence Lessig; “The Future of Ideas: The Fate of the Commons in a Connected World”
- Lawrence Lessig, “Free Culture”
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External References
- Open Images
- Creative Commons; “Marking images“; Creative Commons