Hi Craig,
Unfortunately, it’s been a while since I last thought about this issue,
so I don’t recall precisely how I reproduced it. My methodology was,
basically, ‘play around with ftgrid with forced auto-hinting until I
find a character with issues’. And I have a horrible feeling I might
have using the wrong settings in ftgrid in any case...
That being said, I do recall that I needed to go down to very small
sizes to find issues --- when there’s enough space FreeType is already
pretty good at hinting! Trying again with ftgrid, it seems that
characters ⟨ij⟩ in DejaVu Sans at 7.5 ppem are really bad: if you
increase the font size by even 0.5 ppem more they suddenly get a lot
better. Pushing those upper dots just one pixel higher would solve the
issue. For comparison, at 7.5 ppem most other characters in the font are
still quite distinct. If you have access to it, Calibri below 8.5 ppem
also illustrates the problem: the dots on ⟨ij⟩ both nearly vanish at
those sizes. (Incidentally, Calibri’s encoding also allows easy
comparison between the various diacritics, and on that basis I’d say
that ⟨ì⟩ at 8.5 ppem is a reasonable approximation to what I’d want ⟨i⟩
to look like.) And for an example of a font which *doesn’t* have such
great issues, the dots on ⟨ij⟩ in Noto Sans remain fairly distinct even
when the letters themselves are near-illegible.
Regards,
Brad
