The Ubuntu font and a fresh look at open font licensing

When Ubuntu 10.10 was released on October 10, it marked the "official" debut of the Ubuntu Font, commissioned by Canonical from type foundry Dalton Maag. Free software licensing aficionados will no doubt pick up on the fact that the font was released under the "Ubuntu Font License" (UFL) rather than one of the established options. Canonical takes pains to point out that the UFL is an interim license only, though, and the chain of events that led up to its release illustrate the dynamic landscape that is taking shape in the open font community.

The two most widely used licenses for free and open fonts are the Open Font License (OFL), created and stewarded by SIL International, and the General Public License (GPL) with the Font Exception clause. Canonical felt that neither one precisely met the requirements it set out for the ongoing development of the Ubuntu font family, and started private discussions with several members of the open font development community. Ultimately, the need to release the font under clear terms for inclusion Ubuntu 10.10 dictated that the company adopt an interim license, and continue working on a more permanent solution.

The Ubuntu Font Family as a project

Part of the difficulty in finding a "perfect match" license stemmed from the fact that Ubuntu is keen on continuing to develop the font family as a community project, with large contributions from designers outside Canonical and Dalton Maag, but branded under the Ubuntu label. While the initial font release includes Regular, Bold, Italic, and Bold Italic faces, and covers the Latin, Greek, and Cyrillic alphabets, the long-term plan is to add additional scripts and writing systems in regular point-releases.

Paul Sladen, who is a contractor working on the font family for Canonical, explained the basic plan and structure of the project. Dalton Maag is only contracted to deliver five scripts — Latin, Cyrillic, Greek, Arabic, and Hebrew — although Sladen hopes that the foundry will remain involved. That wide Unicode coverage will establish a base style for the font family, and more and more community material will be merged in as time goes by. The first such contribution has actually been merged: the Indian Rupee symbol; its inclusion makes Ubuntu 10.10 the first operating system to ship with out-of-the-box support for the currency symbol.

The font family is a project hosted on Launchpad, where contributions are beginning to trickle in for additional character sets. For new scripts (and presumably other large-scale enhancement efforts), Sladen said that the current plan, though not set in stone, "is that each LoCo group find themselves two type designers, document the additions necessary for their script, and in order to maintain stylistic harmony across the font family one of those type designers would be mentored by Dalton Maag. Each script would be focused on in turn, on a two-month rotation (eg. potentially six new written scripts or languages per year)." Point releases (1.10, 1.20, etc.), he added, would add beta support for the new scripts, while assuring that the font metrics for those glyphs that were already in the stable (x.00) release remain unaltered, to protect existing documents against sudden repagination and alignment problems.

This structured development plan is distinctly different from the process seen in previous open font commissions, such as the Liberation fonts developed by Ascender for Red Hat. Development has continued on the Liberation family, but without plans specifically targeting greater Unicode coverage.

Licensing decisions

There are derivatives of Liberation that do set out to build wide support for other writing systems though, notably the DejaVu fonts project. This highlights one of the principle issues that separate different open font licensing options: simply examining the names, a user would have no idea that the DejaVu family is related to Liberation.

Canonical considered both the OFL and GPL with Font Exception when beginning its search for a license under which to release the Ubuntu font family. For those unfamiliar, although both licenses are designed to permit modification and redistribution of fonts, they do feature several important differences.

First, the OFL does not require availability of source code. In practice, though, it is easy to modify fonts based only on their binary representation (such as .TTF or .OTF files). For derivative fonts, OFL requires the derivative maker to obtain permission from the original copyright holder in order to re-use the "Reserved Font Name" of the original. Finally, OFL includes a clause that does not allow the font to be re-sold by itself. The latter two elements illustrate that the OFL is designed to meet the expectations of type designers. In particular, the "Reserved Font Name" preservation is an important issue because copyright and patent law varies greatly between different countries in regard to fonts; as a result many type designers rely on protecting the name of the original as the primary line of defense against "brand" dilution.

The GPL with Font Exception, as one might expect, does require source code availability and does not restrict commercial sale of the font. It does not, however, explicitly address renaming derivative works. The Font Exception clause itself simply specifies that documents created with the font are not considered derivative works of the font. The OFL has a similar clause.

While planning for the release of the font, Canonical undertook discussions that reportedly involved OFL co-author Nicolas Spalinger and the Open Font Library's Dave Crossland, seeking to find a licensing approach that would meet Ubuntu's precise needs — a set of concerns that seemed to fit neither OFL nor the GPL with Font Exception. Lacking a perfect fit, Canonical then drafted the interim UFL for the font, following the same broad structure as the OFL.

All of the parties were quick to emphasize that there was nothing adversarial about the discussions, nor the eventual decision to create the UFL. Sladen posted a diff between the interim UFL and the latest version of the OFL (1.1) that shed some light on what Canonical's needs were, however. There are slight differences in wording (such as the use of "propagate" instead of "distribute") that seem to place the license more in line with the GPL and LGPL used for Ubuntu software, but the biggest significant change is in the UFL's treatment of derivative font naming.

First, while the OFL establishes the concept of a "Reserved Font Name" that original copyright holder retains control over, the UFL specifies three distinct degrees of font derivative, and applies specific naming instructions to each. Unmodified versions of the original font must retain the original name, modified versions that are not "Substantially Changed" must be renamed to append the derivative name to the original name, and modified versions that are "Substantially Changed" must be renamed entirely.

The term "Substantially Changed" is defined in the license as "Modified Versions which can be easily identified as dissimilar to the Font Software by users of the Font Software comparing the Original Version with the Modified Version." The distinct degrees of modification and the explicit requirements for each take the place the OFL's requirement that recipients of the font seek explicit permission from the copyright holder on naming questions. The UFL further specifies that the license does not grant any rights to trademarks associated with the original font.

Consequently, the UFL allows "substantial" and "unsubstantial" forks of the Ubuntu font family, but attempts to encode in the license itself what the fork creators must do regarding the font name, and it simultaneously seeks to protect Canonical's trademark on the Ubuntu name itself.

Future licenses, and future code

Although Canonical is clearly satisfied that the terms of the UFL perform their intended function, the company maintains that the UFL is only a temporary solution, and that within several months, a permanent license will be selected. The trouble is that Canonical is not interested in being a license steward, feeling both that license stewardship is outside of its core mission, and that licenses should be maintained by wider community efforts.

While no one is in favor of license proliferation, it is clear that different people and groups involved in open font development represent a spectrum of different beliefs. Crossland believes that this spectrum would best be served by a clear set of license choices, along the lines provided by Creative Commons for artistic works. The Open Font Library's goal of creating strong copyleft fonts, for example, might best be supported by the GPL with Font Exception. SIL's interest in attracting professional type designers to work on modifiable, redistributable fonts is best supported by the OFL.

Thus it seems like a new open font license is inevitable, whether it is eventually maintained by SIL, the FSF, or some other party altogether. Who that might be is entirely up in the air. SIL might seem like the obvious choice, given its long history with the open font movement, but one should not expect a "L"OFL to appear suddenly. Spalinger discussed the UFL and Ubuntu font family project on his blog, and although he emphasizes that he is not speaking on behalf of SIL, he makes it a point that stewardship of another license is not a task that SIL is likely to undertake lightly, nor without support and input from the wider open font community.

Spalinger also has considerable praise for the practical benefits that the Ubuntu font project have brought about, including the fonttest web application, the ongoing efforts of Dalton Maag and Canonical's Design Team to publicly document the font design and testing process on its blog, and Canonical's plan to continue to the develop the font family in the open.

Regarding Dalton Maag, Sladen was also happy that the foundry (and Bruno Maag in particular) was reacting warmly to the interaction with the Ubuntu community. Many foundries, he said, are not used to the long, iterative feedback-and-tweak cycle that this particular commission carried with it — typically, a foundry finishes the design, delivers it to the client, deposits its check, and is finished. "It was a slow start, it is a complete mindset change for them," he said, "I think Dalton Maag have realised the value of the publicity."

At the same time, Dalton Maag's involvement with the project is also having an impact on the open source font creation tool set. Initially, Sladen said, Canonical tried to find a type foundry that worked with open source tools — and there were none.

Instead, Dalton Maag is providing constructive feedback on FontForge and other open source font applications, from the perspective of a full-time type foundry. "Ubuntu focuses quite a lot on usability and user-interaction; before you can fix things, you need to work out what is broken, and precisely the same applies to the libre-font creation stack." He cited several pieces missing from the open source type design process, such as digital signatures and visual hinting and layout tools that the community needs to work together to replace.

Crossland said that type design is in the midst of a revolution at the moment, after years of stability, brought about by Web Font support. As a result, the open font community has grown significantly in recent years, but a side effect of that growth is the differentiation of different participants' goals and needs. One license will probably never fit all. On the bright side, the artistic community has thrived with Creative Commons' palette of licenses, and the free software movement has never been held back by supporting multiple license options. Fonts and their unique set of issues are simply coming of age.