OpenType Salt Feature

Michael JarboeMichael Jarboe Posts: 265
edited November 2015 in Technique and Theory
Is it just personal preference, and the ability to make some alternate glyphs accessible in Adobe Illustrator as for the reason to include 'Salt' as opposed to just including a series of Stylistic Sets SS01 etc.?

I'm curious if designers have different practices with their approach to stylistic alternates, or what is considered best practice?


  • I haven't used Illustrator CC yet (I'm on CS6), so I'm not sure if that has changed, but in CS6 and below, stylistic sets aren't included in Illustrator's Open Type panel - the only option given is for "stylistic alternates", so you can only have 1 set of alternates. The only other way to access the alt glyphs is manually selecting them from the glyphs panel. (At least, I think so)
  • This is true of the Illustrator CC as well. Illustrator has support for 'salt' (via a button on the OT panel) but not stylistic sets. Although it does let you filter the Glyph palette by any feature in the font, including stylistic sets. Not sure if this was true in earlier versions.
  • Still on CS6 myself, Erin.
  • Michael JarboeMichael Jarboe Posts: 265
    edited November 2015
    I guess another thing I'm wondering is if I currently have an SS01 and SS02 does it make sense to change SS01 into Salt and SS01 into SS02 (therefore ending up with only Salt and SS01 as the stylistic alternate features, with both addressing separate features)?

    Or should I just stick with the former and add Salt in addition to SS01 and SS02 making it address the same alternates as SS01 (therefore ending up with Salt/SS01 & SS02 as the alternate features)?

    Are said choices concerning Salt primarily motivated by Illustrator's (are there other apps with the same limitations?) OpenType limitation?

    Is doubling up and having Salt/SS01 addressing the same stylistic alternate features not good practice?

    Is there any other reason to implement Salt or not if you're dealing with more than one set of stylistic alternate features?
  • Is doubling up and having Salt/SS01 addressing the same stylistic alternate features not good practice?

    It's fine. It doesn't hurt anything and it covers the major use cases.

  • The problem is that salt is not supported by Indesign. 
  • The problem is that salt is not supported by Indesign. 
    It's true in standard indesign (english).
    Salt is suported in english-hebrew or english-arabic indesign or You can use this script in any indesign since CS4:

    main ();

    function main ()
    if (app.selection[0].otfStylisticAlternate == true)
    app.selection[0].otfStylisticAlternate = false;
    app.selection[0].otfStylisticAlternate = true
    catch (_){}


  • Adam TwardochAdam Twardoch Posts: 507
    edited November 2015
    When I develop OpenType features, I typically pair ssXX and salt as this:

       feature ss01 { sub a by a.ss01; sub b by b.ss01; } ss01; feature ss02 { sub b by b.ss02; } ss02; feature ss03 { sub a by a.ss03; } ss03; feature salt { sub a from [a.ss01 a.ss03]; sub b from [b.ss01 b.ss02]; } salt;  

     In other words, the "salt" feature in my implementations is a "logical sum" of all stylistic set features.
  • In Illustrator, only the first enumerated variant (equivalent to ss01) will be accessible through the "salt" toggle in the OpenType palette. The other variants will be only available via the Glyph palette popups. But I consider this nonetheless the "technically correct" implementation. The "salt" feature can use one-to-one-out-of-many substitutions, according to the spec. It's one of the oldest features, well-predating stylistic sets. Ideally of course, apps such as Illustrator should implement stylistic sets as well. 
  • Adam, my features are written a bit differently, how would I turn these into a Salt feature similar to your example?

    feature ss01 {
        sub @ss011 by @ss012;
    } ss01;


    feature ss02 {
        sub N degree by numero;
        sub N ordmasculine by numero;
    } ss02;
  • I usually avoid using the salt feature in fonts that have much in the way of contextual features. In Illustrator if you are typing your text as opposed to pasting it in and happen to switch a glyph out that is under the salt feature, the salt feature remains active and ends up canceling out other features.
  • John HudsonJohn Hudson Posts: 2,872
    I don't think I've included the 'salt' feature in any fonts since we registered the 'ssXX' feature set.
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