Stylistic Set Consistency Between Styles

Wei Huang

What do you do when the stylistic sets are not consistent across styles, how do you number it?

Simple example,
Upright has:
a.ss01
l.ss02
g.ss03

but Italic only has
l.ss02

Do you keep redundant stylistic set features in the other styles, is it necessary? 

Khaled Hosny

I’d make the numbers unique across the family, so if italic’s ss02 is not the same as upright’s, I’d name ut ss04. This way if you apply ss02 on the whole text you don’t get different results for different styles. Other than that missing sets from one style shouldn’t be an issue IMHO.

John Hudson

If I have some stylistic sets that apply across multiple styles, and some that only apply to some styles, I'll try to order them in a way that proceeds from common to individual, e.g.:

Upright styles:
l.ss01
a.ss02
b.ss03

Italic styles:
l.ss01

I don't think it's a requirement that stylistic sets follow alphabetic order of the glyphs they affect. [That's not actually what the stylistic set features are for: they're meant to affect stylistic variation across groups of glyphs, not individual letters, but I understand why people use them in this way given poor support for the Character Variants features.]


Sometimes, due to extension of existing fonts with new stylistic set features, this ordered approach isn't an option, so in that case I'm perfectly willing for some fonts to have only select features, e.g.:

Upright styles:
a.ss01
l.ss02
g.ss03

Italic styles:
l.ss02


I have even applied this approach across fonts that are not technically part of the same family. So, for instance, the Murty Hindi font has more stylistic set features than the Murty Sanskrit font, but those that the latter does have match the numbering of corresponding features in the former.

Kent Lew

For reasons that John and Khaled have already expressed, when I used to work on features for Font Bureau fonts, I would handle Stylistic Sets within a family similarly.

For example, Cyrus Highsmith is fond of offering both both single- and double-story a’s and g’s in a lot of his fonts. When the roman has double-story as the default and the italic has single-story as default, then I would make sure to separate the Stylistic Sets so that there was no conflicting overlap.

That is to say, Stylistic Set 1 might change double-story g to single-story in roman styles, while it would do nothing in the italic styles. Conversely, Stylistic Set 2 would change single-story to double-story in italic styles, but do nothing in roman.

That way, if a user wanted single-story roman g’s in a setting and applied Stylistic Set 1 to the whole paragraph, any italic in the mix wouldn’t unexpectedly change to double-story.

There is nothing that requires one to have consecutive Stylistic Set numbers within a font. You can skip any that you want. You can write a single {ss20} if that suits your whim.

The numbering, ordering, and composition of Stylistic Sets is largely at the discretion of the designer or font engineer.