Garamond Premier Pro has four: Display, Subhead, standard, and Caption. The four optical sizes differ in overall weight, and intra-glyph stroke weight variation, for any given weight value.
Take a look, for example, at this page on readthesequences.com. The body text is in Garamond Premier Pro Regular (i.e. 400 weight). The heading, on the other hand, is in Garamond Premier Pro Subhead Medium (i.e. 500 weight, and a different optical size).
The Display optical size is for the largest headings. (As the post title is displayed at 50px size, this optical size may be appropriate here, or it may not.)
The Subhead optical size is for all headings except the very largest ones. (This optical size may be appropriate for the post title, and is certainly appropriate for all other heading levels within a post.)
The standard optical size is for body text.
The Caption optical size is, as the name indicates, for small text like captions, as well as superscript footnote links, etc.
Edit: This was supposed to be a reply to Raemon’s comment—whoops.
Yeah, I am still planning to do that, but held off on it since it increased our bundle size too much, and I needed to do some optimizations first. In general the current font changes are just a hotfix for the readability issues on various devices, and I am still working on a larger typography rework (I have access to Garamond Premier Pro via my Typekit subscription, so me using this font is not a sign that I paid for it and so settled on it as being used in the future, so that might also still change).
Cool. FYI re: increasing bundle size: indeed, I agree that this is a concern. My suggestion is to make use of subsetting—which you probably know about… but the non-obvious bit of the suggestion is this:
For font variants intended to be used for headings, you can get away with grabbing a much smaller subset of glyphs (as headings are unlikely to contain characters of other languages, or small caps, or exotic punctuation, or… etc.) than you need for the body text font variant.
This can cut down on the resulting file size by quite a bit (especially when starting with a font which contains as exhaustive a set of glyphs as Garamond Premier Pro, or most other professional fonts).
What you want to do is to vary optical sizes.
Garamond Premier Pro has four: Display, Subhead, standard, and Caption. The four optical sizes differ in overall weight, and intra-glyph stroke weight variation, for any given weight value.
Take a look, for example, at this page on readthesequences.com. The body text is in Garamond Premier Pro Regular (i.e. 400 weight). The heading, on the other hand, is in Garamond Premier Pro Subhead Medium (i.e. 500 weight, and a different optical size).
The Display optical size is for the largest headings. (As the post title is displayed at 50px size, this optical size may be appropriate here, or it may not.)
The Subhead optical size is for all headings except the very largest ones. (This optical size may be appropriate for the post title, and is certainly appropriate for all other heading levels within a post.)
The standard optical size is for body text.
The Caption optical size is, as the name indicates, for small text like captions, as well as superscript footnote links, etc.
Edit: This was supposed to be a reply to Raemon’s comment—whoops.
Yeah, I am still planning to do that, but held off on it since it increased our bundle size too much, and I needed to do some optimizations first. In general the current font changes are just a hotfix for the readability issues on various devices, and I am still working on a larger typography rework (I have access to Garamond Premier Pro via my Typekit subscription, so me using this font is not a sign that I paid for it and so settled on it as being used in the future, so that might also still change).
Cool. FYI re: increasing bundle size: indeed, I agree that this is a concern. My suggestion is to make use of subsetting—which you probably know about… but the non-obvious bit of the suggestion is this:
For font variants intended to be used for headings, you can get away with grabbing a much smaller subset of glyphs (as headings are unlikely to contain characters of other languages, or small caps, or exotic punctuation, or… etc.) than you need for the body text font variant.
This can cut down on the resulting file size by quite a bit (especially when starting with a font which contains as exhaustive a set of glyphs as Garamond Premier Pro, or most other professional fonts).