On a website with German content we are integrating a custom font via Adobe TypeKit (Basel Neue) using the standard script. However the font will display any occurrence of ss as ß instead - which does not make sense in many cases (e.g. Wasser will be displayed as Waßer etc.).
I am not sure if this is an OpenType feature and thus can be controlled via CSS settings. I was unable to identify such an OpenType feature here at least. I also can't find any info on the web for such a case - only info about the other way around (ß to ss).
Does anyone have any idea why this happens or whether a TypeKit setting can control this behavior?
To me it looks like ligatures issues. Try this:
font-variant-ligatures: normal;
font-variant-ligatures: none;
font-variant-ligatures: common-ligatures; /* <common-lig-values> */
font-variant-ligatures: no-common-ligatures; /* <common-lig-values> */
font-variant-ligatures: discretionary-ligatures; /* <discretionary-lig-values> */
font-variant-ligatures: no-discretionary-ligatures; /* <discretionary-lig-values> */
font-variant-ligatures: historical-ligatures; /* <historical-lig-values> */
font-variant-ligatures: no-historical-ligatures; /* <historical-lig-values> */
font-variant-ligatures: contextual; /* <contextual-alt-values> */
font-variant-ligatures: no-contextual; /* <contextual-alt-values> */
font-variant-ligatures: contextual; /* <no-historical-ligatures> <common-ligatures> */
/* Global values */
font-variant-ligatures: inherit;
font-variant-ligatures: initial;
font-variant-ligatures: unset;
from MDN: https://developer.mozilla.org/en/docs/Web/CSS/font-variant-ligatures