Im currently working on an uppercase font and the process is mostly straight forward but the integration of letter ß (Eszett) is i a major problem. There is an uppercase version and a lovercase version for this glyph (ẞ ß) but they are not linked inside Fontself resulting in either a Font with a missing characters or a font with fallback letters for all lowercase versions of the Latin alphabet.
This seems like bug in the automated substitution process of Fontself. Using the uppercase version of ẞ should automatically create the same lowercase version.
As I understand it, a fallback is not a task or part of the character set, but of the programme/system that represents the font. In Illustrator, for example, the programme tries to replace missing glyphs, see second picture. On the web or in e-books, more than one font is also stored in the source text for this reason. A solution by ligature might be possible, but then a third character would have to be added to distinguish between a real spelling of SS and SS’.liga = capital ß. Doesn’t seem to me to be a real solution either.
