A lovely visual essay from Letterform Archive on the photo-typesetting era — a narrow twenty-year window when type was made of light instead of metal or pixels. The kerning was awful and the optical sizes were perfect.
What’s striking, looking back, is how much character was preserved by the constraints. The film masters had to commit to a small set of optical sizes, and the shift to digital flattened all of that into one drawing scaled mathematically. Variable fonts are finally bringing some of it back.