Managing Reserved Font Names (RFNs)

What are Reserved Font Names (RFNs)?

These are font names, or portions of font names, that the author has chosen to reserve for use only with the Original Version of the font, or for Modified Version(s) created by the original author. These are declared in the OFL.txt file after any corresponding copyright declarations. For example, the Gentium project has two RFNs:

Copyright (c) 2003-2023 SIL International (, with Reserved Font Names “Gentium” and “SIL”.

If any RFNs are declared for a font, then Modified Version(s) of that font made by anyone other than the copyright holder cannot use those RFNs in the font name.

Can fonts with RFNs be converted into webfont formats without changing the name?

This is a complex issue. The answer depends on the format and processes used. We have a separate page dedicated to these issues: Webfonts and Reserved Font Names.

Should I declare RFNs for fonts I create?

We generally recommend the use of RFNs. There are some key benefits:

  • Avoids collisions - it greatly reduces the likelihood that a Modified Version would get confused with the Original Version, whether by an end user, someone bundling the font into a separate app or collection, or an application attempting to render a document that specifies a particular font.
  • Protects authors - it requires any font that bears the RFNs retain the functionality and quality of the Original Version.
  • Minimizes support - it enables authors to adequately support their fonts without the burden of troubleshooting fonts bearing the same name that might have been poorly modified.
  • Encourages derivatives - it encourages separately-named forks and branches to exist and be properly identified so that new, interesting enhancements can get reviewed and eventually merged back into the main project.

When should I not declare RFNs?

There are situations in which you (the copyright holder) may not want to declare an RFN:

  • If you want to give others the freedom to modify the font and release it under the same name. For example, if you want to contribute a font to an open source project and want to allow others to modify the font but retain the name.
  • If you don’t feel you can claim exclusive use of a name, such as when a font includes a language or script name. For example, the font project Lisu Bosa does not declare “Lisu” as an RFN, as it is the name of a language and script, but does declare “Bosa”.
  • If the foundry or service publishing the font needs the freedom to make substantial adjustments but wants to keep the font name. There is an alternative to this - see next section.

Individual RFN agreements

If you wish to give someone the right to modify your font but still use your RFNs, you can sign a separate agreement with them that gives them that permission. There is no prescribed format for this agreement, as legal systems vary. You may wish to add specific clauses to further restrict use, require author review of Modified Versions, establish user support mechanisms or provide terms for ending the agreement. Such agreements are usually not public, and apply only to the main parties. However, it may be beneficial to state when such agreements have been established, so that the public is clear that the Modified Version is using the RFN with permission.

Such agreements normally don’t transfer to other parties. For example, FFF Foundry may give ABC Corp permission to use their RFN “Foo” and distribute a Modified Version called “Foo”. XYZ Ltd, however, cannot further modify that font and release it using “Foo” unless they also sign an agreement with FFF Foundry.

There has been interest by the wider OFL community in a service or web application that would make it very easy for authors to give RFN permission to specific webfont services. This is a great idea, however since it would need to be separate from the OFL itself, it would be inappropriate for SIL, as primary maintainers and stewards of the OFL, to run or control such a service.

Specific answers from the OFL-FAQ

The following questions and answers are color-coded to help make it easier to understand, but please do click on the question to reveal the answer and read through the details. This is only a small subset of the questions and answers available in the OFL-FAQ. Please read the full OFL-FAQ for in-depth information.

Green generally means yes. Red generally means no. Yellow means it depends on the situation. Blue means informational.

These are font names, or portions of font names, that the author has chosen to reserve for use only with the Original Version of the font, or for Modified Version(s) created by the original author.
The best way to acknowledge the source of the design is to thank the original authors and any other contributors in the files that are distributed with your revised font (although no acknowledgement is required). The FONTLOG is a natural place to do this. Reserved Font Names ensure that the only fonts that have the original names are the unmodified Original Versions. This allows designers to maintain artistic integrity while allowing collaboration to happen. It eliminates potential confusion and name conflicts. When choosing a name, be creative and avoid names that reuse almost all the same letters in the same order or sound like the original. It will help everyone if Original Versions and Modified Versions can easily be distinguished from one another and from other derivatives. Any substitution and matching mechanism is outside the scope of the license.
Yes, this applies to the font menu name and other mechanisms that specify a font in a document. It would be fine, however, to keep a text reference to the original fonts in the description field, in your modified source file or in documentation provided alongside your derivative as long as no one could be confused that your modified source is the original. But you cannot use the Reserved Font Names in any way to identify the font to the user (unless the Copyright Holder(s) allow(s) it through a separate agreement). Users who install derivatives (Modified Versions) on their systems should not see any of the original Reserved Font Names in their font menus, for example. Again, this is to ensure that users are not confused and do not mistake one font for another and so expect features only another derivative or the Original Version can actually offer.
You may not use individual words from the Reserved Font Names, but you would be allowed to use parts of words, as long as you do not use any word from the Reserved Font Names entirely. We do not recommend using parts of words because of potential confusion, but it is allowed. For example, if “Foobar” was a Reserved Font Name, you would be allowed to use “Foo” or “bar”, although we would not recommend it. Such an unfortunate choice would confuse the users of your fonts as well as make it harder for other designers to contribute.
Original authors are encouraged to name their fonts using clear, distinct names, and only declare the unique parts of the name as Reserved Font Names. For example, the author of a font called “Foobar Sans” would declare “Foobar” as a Reserved Font Name, but not “Sans”, as that is a common typographical term, and may be a useful word to use in a derivative font name. Reserved Font Names should also be single words for simplicity and legibility. A font called “Flowing River” should have Reserved Font Names “Flowing” and “River”, not “Flowing River”. You also need to be very careful about reserving font names which are already linked to trademarks (whether registered or not) which you do not own.
No. RFNs are optional and not required, but we encourage you to use them. This is primarily to avoid confusion between your work and Modified Versions. As an author you can release a font under the OFL and not declare any Reserved Font Names. There may be situations where you find that using no RFNs and letting your font be changed and modified - including any kind of modification - without having to change the original name is desirable. However you need to be fully aware of the consequences. There will be no direct way for end-users and other designers to distinguish your Original Version from many Modified Versions that may be created. You have to trust whoever is making the changes and the optimizations to not introduce problematic changes. The RFNs you choose for your own creation have value to you as an author because they allow you to maintain artistic integrity and keep some control over the distribution channel to your end-users. For discussion of RFNs and webfonts see section 2.
No. That is a change to the license as of version 1.1. If you want any names to be Reserved Font Names, they must be specified after the copyright statement(s).
The Copyright Holder(s) can give certain trusted parties the right to use any of the Reserved Font Names through separate written agreements. For example, even if “Foobar” is an RFN, you could write up an agreement to give company “XYZ” the right to distribute a modified version with a name that includes “Foobar”. This allows for freedom without confusion. The existence of such an agreement should be made as clear as possible to downstream users and designers in the distribution package and the relevant documentation. They need to know if they are a party to the agreement or not and what they are practically allowed to do or not even if all the details of the agreement are not public.
Yes, all rebuilds which change the font data and the smart code are Modified Versions and the requirements of the OFL apply: you need to respect what the Author(s) have chosen in terms of Reserved Font Names. However if a package (or installer) is simply a wrapper or a compressed structure around the final font - leaving them intact on the inside - then no name change is required. Please get in touch with the author(s) and copyright holder(s) to inquire about the presence of font sources beyond the final font file(s) and the recommended build path. That build path may very well be non-trivial and hard to reproduce accurately by the maintainer. If a full font build path is made available by the upstream author(s) please be aware that any regressions and changes you may introduce when doing a rebuild for packaging purposes is your responsibility as a package maintainer since you are effectively creating a separate branch. You should make it very clear to your users that your rebuilt version is not the canonical one from upstream.
Yes. List your additional Reserved Font Names after your additional copyright statement, as indicated with example placeholders at the top of the OFL.txt file. Be sure you do not remove any existing RFNs but only add your own. RFN statements should be placed next to the copyright statement of the relevant author as indicated in the OFL.txt template to make them visible to designers wishing to make their separate version.