Got a font that I want to do a custom subset for on the Web - picking contextual alternates and discarding unneeded characters to help keep the file size down. FontSquirrel has a great generator, but a lot of the fonts come with this notification:

The license for this font is the SIL OFL license. This license does not allow us to redistribute derivative versions of the font without wholesale name changes inside and out of the font. Until we figure out a reasonable method of delivering these to you and complying with the license, you will have to use the Webfont Generator yourself on these, renaming the fonts appropriately.

What constitutes as 'wholesale name changes inside and out of the font'? I want to comply with what seems to be an excellent license correctly.

Suppose it's also worth asking what constitutes a derivative work as well. The font I'm interested in is available on Google Fonts, and it seems like a custom subset was made to distribute on their CDN. Is subsetting not something that triggers this stuff at all?

I've been trying to wrap my head around the SIL site but am not doing a very good job.

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    I do not fully understand but it seems to be in reference to the copyright owner having declared Reserved Font Names. The document states : Any modification normally disallows the use of RFNs without a separate agreement, however some ways of preparing the font for use on the web might not be considered to create Modified Versions that would require such an explicit agreement. And then they go on discriminating between technological means which would comply with the license objective etc.
    – user29318
    Nov 20, 2014 at 4:05
  • @Amphiteóth - yeah, that seems to be the most important part. If you want to throw that in as an answer you're welcome to; otherwise, I'll post up an answer with some of the process I went through to arrive at my solution.
    – Brendan
    Nov 21, 2014 at 1:43
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    It's just weird to me that I would make no meaningful changes to the font other than reduce the number of glyphs in it and then put my name on it like I made the font myself. It makes sense, though...
    – Brendan
    Nov 21, 2014 at 1:43
  • Why are you putting your name on it if you admit that you have made no meaningful changes? If you rip an song and downsample the quality to a small mp3, you wouldn't put your name on it, would you?
    – Moscarda
    Aug 3, 2017 at 0:39
  • @Moscarda Subsetting is different than downsampling. It'd be more analogous to cutting a verse out of a song and then trying to pass it along as the original. It's a derivative work at that point and should be marked as such. An analogy to music is tough anyways though, as songs aren't open source. It's not super uncommon in the open source world to do something like fork a project, change one tiny thing, but then give the whole thing a new name because the name is copyrighted.
    – Brendan
    Aug 3, 2017 at 12:50

1 Answer 1


There's 2 official answers from the SIL site (that maintains and documents the SIL/OFL licence):

Is subsetting a web font considered modification?

Web Fonts and Reserved Font Names

The summary (at least as I unserstand it) is: you are allowed to convert into WOFF format while keeping the reserved font name, as long as you dont subset. Other formats or subsetting are not allowed without changing the name.

They suggest contacting the author to encourage her to release the font without Reserved font name or get a special licence permission to get around this limitation.

Personally, i think it is ridiculous to expect people to rename open source fonts because they subset or convert to another format. I suspect most type designers did not have this in mind when they chose this licence,

  • Why do you think it's ridiculous? If someone were to subset and then people had issues with the subset, wouldn't they go to the copyright holder whereas he's not responsible for the subset? Or what about a subset which is so reworked as to be a powerful modification - then wouldn't it be appropriate that this rename gains mindshare on its own. I am not a professional in the field but I'd really like to understand your opinion on that. Thank you!
    – user29318
    Nov 21, 2014 at 13:05
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    You have good points, on the other hand if anyone that wants to use the font in their website and does the converting themselves has to have a different name and we wind up with 300 different names for the same font. Unnecessary since converting and subsetting are not , in my opinion,substantially modifying the font. I cannot think of a concrete scenario where either could be considered powerful enough to make it a different font.
    – spiral
    Nov 24, 2014 at 9:00

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