If an "intellectual work" (a song, a book, a computer program, ...) is in the public domain (PD), it has no "owner", meaning no one has any exclusive rights (such as [copyright](copyright.md) or [patent](patent.md)) over the work, no one can dictate how and by whom such work can be used and so anyone can basically do anything with such work (anything that's not otherwise illegal of course).
[LRS](lrs.md) highly supports public domain and recommends programmers and artists put their works in the public domain using [waivers](waiver.md) such as [CC0](cc0.md).
Public domain is the ultimate form of freedom in the creative world. In public domain the creativity of people is not restricted. Anyone can study, remix, share and improve public domain works in any way, without a fear of being legally bullied by someone else.
Public domain is NOT the same thing as [free (as in freedom) software](free_software.md), [free culture](free_culture.md) or freeware (gratis, free as in beer) software. The differences are these:
- Unlike public domain, **[free software](free_software.md) and [free cultural](free_culture.md) works are usually still "owned" by someone**, they just try to relax the rules and make them less oppressive. A public domain work is completely unlimited and belongs to everyone and no one, while free software/culture may still require and legally enforce certain freedom-compatible conditions such as giving credit to the author or [copyleft](copyleft.md).
- **Public domain software is not always [free software](free_software.md)** -- PD software is free (as in freedom) only if its source code is available and also in the public domain (without source code freedoms 1 and 2 in the definition of free software are violated).
- **Freeware/gratis just means available for no price**, very often under specific restrictive conditions such as "for personal use" only and without the access to the source code. Public domain is not only gratis but also without any legal limitations on use.
## Which Works Are In The Public Domain?
This is not a trivial question, firstly because the term *public domain* is not clearly defined: the definition varies by each country's laws, and secondly because it is non-trivial and sometimes very difficult to assess the legal status of a work.
Corporations and [capitalism](capitalism.md) are highly hostile towards public domain and try to destroy it, make it effectively non-existing, as to eliminate "free" works competing with the consumerist creations of the industry. Over many years they have pushes towards creating laws that make it extremely difficult and rare for works to fall into public domain.
Sadly due to these shitty laws most works created in latest decades are NOT in the public domain because of the [copyright](copyright.md) [cancer](cancer.md): copyright is granted automatically, without any registration or fee, to the author of any shitty artistic creation, and its term lasts mostly for **the whole life of the author plus 70 years!** In some countries this is life + 100 years. In the US, copyright lasts 96 years from the publication of the work (every January 1st there is so called public domain day celebrating new works entering the US public domain). In some countries it is not even possible to legally waive (give up) one's copyright. And to make matters worse, copyright isn't the only possible restriction of an intellectual work, there are also [patents](patent.md), [trademarks](trademark.md) and other kinds of [intellectual property](intellectual_property.md).
Another bad news is that works in a **"weak" public domain**, i.e. most recent PD works or works that entered PD by some obscure little law, may as well stop being PD by introducing some shitty retroactive law (which has happened). So one may not be feeling completely safe going crazy by utilizing some recent PD works.
We therefore devise the term **safe/strong public domain**. Under this we include works that are pretty safely PD more or less world-wide, even considering possible changes in laws etc. Let us include these works:
- Works published at least 100 years ago whose author probably died at least 70 years ago.
- Works **clearly and properly** marked by a reliable PD [waiver](waiver.md) such as [CC0](cc0.md). However an extra effort needs to be taken to assure that the work e.g. isn't a derivative work of copyrighted work, or that patents are waived with software.
- Works that under any "reasonable" law can not be covered by "intellectual property", e.g. math equations, colors etc.
[Creative commons](creative_commons.md) has created a **public domain mark** that helps mark and find works that should be in a world-wide public domain (this is not a waiver though, it is basically only used as a metadata for very old works to be better searchable).
There are a number of places on the internet to look for public domain works, for a list see below.
## How To Create Public Domain Works
If you want to create a PD work (which you should), then generally in that work **you must not use any non-public domain work**. So, for example, you can NOT create a public domain fan fiction story about Harry Potter because Harry Potter and his universe is copyrighted. Similarly you can't just use randomly googled images in a game you created because the images are most likely copyrighted. Small and obscure exceptions (fonts, freedom of panorama, ...) to this may exist in laws but it's never good to rely on them, it's best to keep it safe and simply avoid utilizing anything non-PD within your works.
Also **you can NOT use anything under [fair use](fair_use.md)**! Even though you could lawfully use someone else's copyrighted work under fair use, inclusion of such material would, by the fair use rules, limit what other would be able to do with your work, making it restricted and therefore not public domain. Example: you can probably write a noncommercial Harry Potter fan fiction and share it with friends on the internet because that's fair use, however this fan fiction can never be public domain because it can't e.g. be used commercially, that would no longer fall under fair use, i.e. there is a non-commercial-use-only restriction burdening your work. It doesn't even help if you get an explicit permission to use a copyrighted work in your work unless such permission grants all the right to everyone (not just your work). { I got a mascot removed from [SuperTuxKart](supertuxkart.md) by this argument, mere author's permission to use his work isn't enough to make it free as in freedom. ~drummyfish }
So you can only use your own original creations and other public domain works within your PD work. Here you should highly prefer your own creations because that is legally the safest, no one can ever challenge your right to reuse your own creation, but there is a low but considerable chance that someone else's PD work isn't actually PD or will seize to be PD by some retroactive law change. So when it only takes a small effort to e.g. photograph your own textures for a game instead of using someone else's PD textures, choose to use your own.
{ NOTE: The above is kind of arguing for reinventing wheels which goes a little bit against our philosophy of remixing and information sharing, but we are forced to do this by the system. We are forced to reinvent wheels to ensure that users of our works can't be legally bullied. ~drummyfish }
In cases where you DO reuse other PD works, try to minimize their number and try to make sure they belong to the actual **safe** public domain (see above). This again minimizes legal risk and additionally makes it easy to document and prove the sources.
As a next step make sure you clearly **document** your work and the sources you use. This means you write down where all the works contained in your work come from, e.g. in your [readme](read_me.md). Explicitly mention which things you have created yourself (*"I, ..., have created everything myself except for X, Y and Z"*) and which things come from other people and where you have found them. It is great to also archive the proofs of the third party source being public domain (e.g. use the [Internet Archive](internet_archive.md) to snapshot the page with a PD texture you've found).
Finally you need to actually release your work into the public domain. It must be stressed that it is NOT enough to write *"my work is public domain"*, this is simply legally insufficient (and in many countries you can't even put your work into public domain which is why you need a more sophisticated tool). You need to use a public domain [waiver](waiver.md) (similar to a [license](license.md)) which you just put alongside your work (e.g. into the `LICENSE` file), plus it is also good to explicitly write (e.g. in your readme) a sentence such as *"I, ..., release this work into public domain under CC0 1.0 (link)"*. Currently the best waiver you can use is [Creative Commons Zero](cc0.md) (CC0) which is what we recommend. However note that CC0 only waives copyright and not other things like [trademarks](trademark.md) or [patents](patent.md), so e.g. for [software](software.md) you might need to add an extra waiver of these things as well.
NOTE: You may be thinking that it doesn't really matter if you waive your rights properly and very clearly if you know you simply won't sue anyone, you may think it's enough to just write "do whatever you want with my creation". But you have to remember others, and even you yourself, can't know if you won't change your mind in the future. A clear waiver is a **guarantee** you provide to others, not just a *vague promise of someone on the internet*, and this guarantee is very valuable, so valuable that whether someone uses your work or not will often come down to this. So waiving your rights properly may increase the popularity and reusability of your work almost as much as the quality of the work itself.
For an example of a project project properly released into public domain see the repository of our [LRS](lrs.md) game [Anarch](anarch.md).
## Where To Find Public Domain Works
There are quite a few places on the Internet where you may find public domain works. But firstly let there be a warning: you always **have to** check the public domain status of works you find, it is extremely common for people on the Internet to not know what public domain is or how it works so you will find many *false positives* that are called public domain but are, in fact, not. This article should have given you a basic how-to on how to recognize and check public domain works. With this said, here is a list of some places to search (of course, this list will rot with time):
- **[Wikimedia Commons](https://commons.wikimedia.org/wiki/Main_Page)**: Contains only free as in freedom works among which are many PD ones. You can search for them with queries such as `cat incategory:cc-zero`. This site is quite reliable and serious about licensing, if you find a work marked as PD here, you can be reasonably sure this information is true.
- **[Internet Archive](https://archive.org/)**: The biggest Internet archive, huge amount of mainly old works such as scanned books and photos. Beware that this site contains all kinds of works from PD to [proprietary](proprietary.md) and works marked as PD should be checked as there can be errors. There is an *advanced search* tool that can help in searching for PD works, for example [this query](https://archive.org/search.php?query=possible-copyright-status%3A%28NOT_IN_COPYRIGHT%29%20OR%20licenseurl%3A%28%22http%3A%2F%2Fcreativecommons.org%2Fpublicdomain%2Fmark%2F1.0%2F%22%29%20OR%20licenseurl%3A%28%22http%3A%2F%2Fcreativecommons.org%2Fpublicdomain%2Fzero%2F1.0%2F%22%29) tries to achieve this.
- **[Opengameart](https://opengameart.org/)**: Site for sharing free as in freedom [game](game.md) art (pictures, 3D models, sounds, ...) among which are many under [CC0](cc0.md), i.e. PD. Submitted works are checked reasonably well so any CC0 work you find here is likely truly PD.
- **[Freesound](https://freesound.org/)**: Site for sharing sound recordings and sound effects, contains many [CC0](CC0.md) sounds that should be PD.
- **[Project Gutenberg](https://www.gutenberg.org/)**: Archive of old digitized books. NOT ALL are PD, but the real old ones should be. Generally books from before the 20th century should be PD.
- **[Stocksnap](https://stocksnap.io)**: Quality photos and "stock images" under [CC0](CC0.md), i.e. PD.
- **[Librivox](https://librivox.org)**: Public domain audiobooks made by volunteers that read PD books from Project Gutenberg.
- **[Wikisource](https://en.wikisource.org/wiki/Main_Page)**: Repository of texts, similar to Project Gutenberg, same rules apply (not all texts here will be PD but the real old ones should be).
- **[Openclipart](http://openclipart.org)**: Vector graphics, all under [CC0](cc0.md), i.e. PD in theory, **however** there do appear pictures that are derivative works of copyrighted works for which of course this is irrelevant. Check very well anything you download from here.
- **[Blendswap](https://www.blendswap.com/)**: Site for exchanging 3D models for [Blender](blender.md), not all models are PD but the ones marked CC0 should be, however **NOT those marked as "fan art"!**
- **[Wikidata](https://www.wikidata.org/wiki/Wikidata:Main_Page)**: Database of "everything", published as a whole under [CC0](cc0.md) which should make it PD, **however** it will contain information about proprietary works which may make this status questionable sometimes. If you only use data that don't fall under this you should be safe.
