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GNU General Public License + Font Exception

The GPL+FE icon I drew. (CC0)

UPDATE: I managed to convince the army of volunteer editors to approve an article I wrote on the GPL+FE (General Public License with font exception clause). This after my initial disastrous foray into wikipedia article posting. For those counting, this is my third approved article on Wikipedia.


Lately, for the Open Siddur Project, I’ve been putting together a font package for more easily distributing extant free/libre licensed Unicode Hebrew fonts. These fonts tend to be licensed with SIL’s Open Font License (e.g., EzraSIL and Cardo), or the GNU General Public License (GPL, e.g., Maxim Iorsh’s Culmus Project fonts). Because of the differences between fonts and other software code in their usage, there arose some conflicts which necessitated an exception to the GPL specifically for fonts. Unfortunately, the GPL font exception statement is somewhat buried in the Free Software Foundations GPL FAQ. Because important information on the GPL+FE is nowhere on the Internet included in one single post, I’ve reformatted it and shared it below.

From the Free Software Foundation’s GNU General Public License FAQ, “How does the GPL apply to fonts?“:

Font licensing is a complex issue which needs serious consideration. The following license exception is experimental but approved for general use. We welcome suggestions on this subject—please see this this explanatory essay and write to licensing@gnu.org.

To use this exception, add this text to the license notice of each file in the package (to the extent possible), at the end of the text that says the file is distributed under the GNU GPL:

As a special exception, if you create a document which uses this font, and embed this font or unaltered portions of this font into the document, this font does not by itself cause the resulting document to be covered by the GNU General Public License. This exception does not however invalidate any other reasons why the document might be covered by the GNU General Public License. If you modify this font, you may extend this exception to your version of the font, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version.

The drafter of the GPL+FE statement above, explained the need for the GPL+FE in the following post, “Font Licensing” (FSF 2005).

Font Licensing

by novalis Contributions — last modified May 17, 2010 16:43

By David “Novalis” Turner

There has been some recent confusion about font licensing. Since I wrote the font exception, let me tell you a bit about where we are, and how we got there, and what this all means to you.

First, in the US, the copyright status of fonts is somewhat confused. A font face — that is, the look of a font, is not copyrightable (see Eltra Corp. v. Ringer, 579 F.2d 294 (4th Cir. 1978)). But font “programs” (truetype fonts, for example) are. Another ruling has extended the definition of “programs” to include certain outline data. Why this outline data is not equivalent to a font face, nobody knows. Helpfully, the copyright office has also issued contradictory statements on this. I don’t know how font copyright works in other countries.

What this means is that no font is going to affect the distributability of a printed document in the US. Further, merely referencing the font (as in the CSS font-face: caslon;) does not create a derivative work of that font. So why did we worry about font licensing at all?

The situation we were considering was one where a font was embedded in a document (rather than merely referenced). Embedding allows a document to be viewed as the author intended it even on machines that don’t have that font installed. So, the document (a copyrighted work) would be derived from the font program (another work). The text of the document, of course, would be unrestricted when distributed without the font.

This isn’t an artifact of the GPL; it’s just the way fonts work. Proprietary fonts often explicitly forbid embedding. So, if you want to send your document off to a printing service, the printing service needs to buy another copy of the font.

I was unhappy with even this amount of influence for fonts, because (a) it’s rarely what font authors intend and (b) it’s possible that some applications do embedding behind the user’s back. The situation seemed to me to be similar to the case of the runtime libraries which GCC automatically includes in its output (and which are licensed to permit inclusion in proprietary software). So, I wrote the font exception you see on our web site.

The reason the exception is so limited is that we’re worried about someone extracting a font from a document, and redistributing it. Extraction is, in my view, the major issue that a font license must confront. Because I haven’t been able to come up with a license which correctly handles embedding and extraction in all cases, I’ve restricted this exception to unaltered fonts. This means that someone can’t use embedding as a way to distribute a modified version of a font under restrictive terms. If you have suggestions for how to write a license which better handles extraction, please let us know. We haven’t had time to give this as much thought as we’ve given some of the other issues involved in free licensing. We’re especially interested in hearing from font creators at licensing@gnu.org.

About Aharon N. Varady


Aharon's Omphalos is the hobbit hole of Aharon Varady, founding director of the Open Siddur Project. He is a community planner and environmental educator working to improve stewardship of the Public Domain, be it the physical and natural commons of urban park systems or the creative and cultural commons of libraries and museums. His advocacy for open-source strategies in the Jewish community has been written about in the Atlantic Magazine, Tablet, and Haaretz. He is particularly interested in pedagogies for advancing ecological wisdom, developing creative and emotional intelligence, and realizing effective theurgical praxes . He welcomes your comments, personal messages, and kind words.

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