[maryz]

I'll bow to you on the proportional typewriters; I'm not sure I ever saw one in person, much less used one. I do recall hearing people hated them.

Further on your side is the fact that memos look sort of like carbon copies, which of course can't be done on a laser printer.

On the other hand, in the phrase "feedback from the 187th," the "th" is superscripted (small and high), the way MSWord does it automatically. Could the proportional typewriters do that?

[JoeA]

I know that they had a font which would allow you to type fractions, one superior and one inferior character, and other math characters. I'm not sure if standard fonts on the typewriter had the sups., but I don't see why they couldn't if the fractions were possible. I'll bet some enterprising freeper can come up with one of those little ball fonts that the IBMs had.

[igoramus987]

The IBM Executive IBM Model D 1967 could do proportional spacing

c.f. link 1 and link 2

Later models of Selectrics replaced inked fabric ribbons with "carbon film" ribbons that had a dry black or colored powder on a "once-thru" clear plastic tape. These could be used only once but they were in a cartridge that was simple to replace. They also introduced auto-correction, where a sticky tape in front of the print ribbon could remove the black-powdered image of a typed character, and introduced selectable "pitch" so that the typewriter could be switched among pica ("10 pitch"), elite ("12 pitch"), and sometimes agate ("15 pitch"), even in one document. Even so, all Selectrics were monospaced -- each and every character was the same width. Although IBM had produced a successful typebar-based machine, the IBM Executive, with proportional spacing, no proportionally-spaced Selectric office typewriter was ever introduced. There was, however, a much more expensive proportionally-spaced machine called the Selectric Composer which was considered a typesetting machine rather than a typewriter.