TTC help required

Nick Shinn

I have recommended a series of size-specific fonts to a client.
However, they would prefer all the opticals for a style to be in one "TTC" font.
I work in FontLab, and this is beyond me.
Is merging three opticals into one font a service that anyone can provide?

George Thomas

Ken Lunde posted a link to information about this in the Build Forum at the other place on February 27. Something new to learn...

John Hudson

Nick, you first need to be clear that your clients understand what a TTC is, and check how they expect to be able to use the font. A TTC is an sfnt file in which (typically) two or more nominal fonts share one or more tables in common. The most frequent implementation is one in which multiple nominal fonts (i.e. fonts with distinct name tables) share a glyf table, usually because they have a significant proportion of glyphs in common. Another implentation would be one in which a number of nominal fonts with identical glyph sets could share a single GSUB table, although the size benefit in that case is likely to be far less.

When we worked on the Sitka fonts for Microsoft, one of the options for implementing size-specific design selection that we explored was to put all of the size-specific designs into a TTC and use a header mechanism to select the appropriate size. Note that this approach would be untypical for TTCs, in that multiple size-specific fonts would appear as a single nominal font. The TTC table format would support this (there's no technical reason why the name table could not be shared in a TTC structure), but existing software enumerates fonts by name table, so some kind of new header would have been necessary. In the end, this approach was eventually rejected in favour of the OS/2 table version 5 revision with size-selection data fields, as implemented in Sitka and now proposed to the ISO Open Font Format standard.

Microsoft have a free tool to build TTCs. It's pretty basic: you give it a set of fonts, it looks for any tables that are identical across the set, and merges into a TTC with identical tables shared and non-identical tables not.

Jeff Kellem

George is likely referring to mention of the tools recently added to the AFDKO for building TTCs. Ken Lunde recently wrote a couple blog posts on it:
http://blogs.adobe.com/CCJKType/2014/01/otc.html
https://blogs.adobe.com/CCJKType/2014/02/otc-redux.html

Nick Shinn

Thanks for your comments.
My client has used the TTC format for opticals before.
I don't use the AFDKO. I tried to install it once, but without success.
A lot of technical stuff is over my head, I just work with FontLab, unembellished.
I would prefer to outsource this, rather than learn something new.

John Hudson

If the client has done this before, then you should get a spec from them on how they want the TTC to be structured and how they expect it to work. Alternatively, they should provide their existing opticals TTC for examination and reverse engineering. I wouldn't even want to quote on a job like this without a clear idea of what is going to be involved.

Nick Shinn

They have provided the TTC fonts they’ve been using, but I can’t open them in FontLab.

Patrick Griffin

There's a Windows build of Fontforge that can make ttc collections quite seamlessly if you know what you're doing. Nick, give me a call. I've done this a few times over the years, so I can give you a hand with this.