Actually, what you describe is an old trend, one particular adaptation necessitated by the limited number of keys available on a standard clankety-clank typewriter keyboard…

Ah, good point. In fact (some) Armenian typewriters replaced three numbers with letters: Ձ, Յ and Օ. And that's where my "Arasan" layout* (used in Windows and OSX... still waiting for official credit) got the idea!

* http://en.wikipedia.org/wiki/Armenian_alphabet#Arasan-compatible

hhp

The “double duty” figures that are designed to work with both U&lc and all caps can be a little weak (narrow, especially, but also light) in all cap settings. So if a font doesn’t have special all cap lining figures (as Shinntype OpenType fonts do), this a good design solution. Here’s another example:

I remember seeing, in the book "Century of the Typewriter", some of the Armenian typewriter layouts to which you refer.

But Nick, a zero almost always has another numeral next to it, so...

hhp

Yes, the 3 in 30ROCK does look a bit narrow, especially to my typographically attuned eyes (which noticed and remembered this in the first place). But overall the substitution does even things out between figures and letters, enough to work for the lay eye, IMHO. Nobody’s going to read it “3 o’rock”! (The color change nails it.)

Well, in that example the symmetry with the "O" in "ROCK" makes it click I think (and "oro" means gold in Spanish :-) but I've seen things like "2012" just by itself with an Oh instead of a zero!

hhp

Actually, what you describe is an old trend, one particular adaptation necessitated by the limited number of keys available on a standard clankety-clank typewriter keyboard…

An old trend indeed. This is what the keyboard layout of Sholes & Glidden Type Writer (a.k.a. Remington No. 1, before 1878) looked like: 43 letters, all caps, no figures 0 and 1, no parentheses and brackets, no exclamation point. In the 1960s I remember using Cyrillic У for Latin V, and figure 1 for Roman numeral I: in Russian typography Roman numerals are used in denoting centuries, thusly: ХУ111–Х1Х вв. But all typewriters in Moscow had Russian keyboard layout! Before decimal (soft-dotted) i (І), yat (Ѣ), fita (Ѳ) and izhitsa (Ѵ) had been dropped in 1918 Russian typists used fita for the V and Cyrillic decimal i for the I: ХѴІІІ–ХІХ вв. That substitution was standard practice in typography too.

When Burmese typewriters came out, they conflated alphabetics with numerals to fit as many characters on as few keys as possible.

Here we have the little ga, numeral 8, curved ya and numeral 7. The two numerals were represented by these letters with similar forms, though the inner loop of the ya was removed, as is sometimes done in handwriting.

Not what you're talking about, I'd imagine, but a number of us replace any "Stempel" zeros (has opposite stress) with a modified "o".

I used to grin & bear those zeros, but Richard Eckersley was having none of it, & we always swapped such zeros out for his books. Harder in the photocomp days, when you had to find another font that matched. Today, we just, gasp, modify the published font.

Anyone who thinks those zeros are cool would steal warm fuzzy things.

Not what you’re talking about, I’d imagine, but a number of us replace any “Stempel” zeros (has opposite stress) with a modified “o”.

I vaguely remember that in his typographic style rules he wrote for Young & Rubicam Klaus Schmidt insisted that in all display copy set in Franklin Gothic the lower-case l should be used in lieu of figure 1.

I do it frequently (O by 0) when I write the current year in a big poster or something like that. It makes the year look maginificent.

Am I misremembering or didn't the OpenType 'consortium' publish a new feature, 'l33t', at the beginning of the month to deal with just this?

So a funny thing happened when I was perusing the fabulous -if labyrinthine- Reading University archives: Fiona Ross was showing me a 1972 typewritten letter from Adrian Frutiger to Walter Tracy, and I immediately noticed something...

At first I couldn't figure out why Frutiger would type a capital Oh where he meant to have a zero, but then I realized that on Swiss typewritters the need to accomodate extra characters probably meant the Oh and zero shared a key! Which BTW is exactly what happened on Armenian typewriters as well: the capitals Ձ, Յ and Օ did double-duty as the 2, 3 and zero (since we have 38 letters)... which BTW is where my Windows/OSX Armenian keyboard layout got that idea.

hhp

Most mechanical typewriters for English etc. had neither a zero nor a one key. Those with lining numerals used an ell, as you see there, and there were also ranging numeral designs that used a capital I. Some even required assembling an exclamation point from a period and a relatively massive straight apostrophe.

@cerulean:
Some even required assembling an exclamation point from a period and a relatively massive straight apostrophe.

Many mechanical typewriters did not have a 1 key, and required one to use the lowercase L instead. Nearly all of those also required one to compose ! from ' and . because ! is normally the shift of 1 in the manual typewriter layout as well as the electric typewriter layout.

However, very few mechanical typewriters did not have a zero. That is for two reasons.

The first is:
( and ) are the shifts of 9 and 0 respectively, and thus omitting the zero would have meant an unconventional location for a vital character. As well, the * - key (or the _ - on an electric) is to the right of the zero key. It's the + = key that got omitted on smaller typewriters.

The second is:
While the lowercase l is, like the numerals on a typewriter, an unshifted character, the capital letter O is a shifted character. Thus, omitting the zero would make numbers much more inconvenient to type, while omitting the one only changes typing a number slightly - one has to find the 1 in a different location, but no extra motions of shifting are required.

So, at least for the typewriters I have experienced in my part of the world, ! is much more often omitted than 0.

( and ) are the shifts of 9 and 0 respectively

On many Armenian typewriters the parentheses (or guillemets, which is what we use for quotes) were moved to 8 and 9. Perhaps that was done for some Latinate languages as well?

hhp

Well, the parentheses are on the 8 and 9 for the bit-pairing ASCII keyboard layout, and the mechanical Teletype layout from which it was derived. Some Japanese PC keyboards are based on the bit-pairing keyboard as well.

As far as mechanical typewriters around the world, I don't have my copy of Century of the Typewriter handy, which is unfortunate, as it has an illustration of the worldwide keyboard layouts offered by Olympia (including an Armenian layout), which would be very germane to this discussion.

As I recall, the zero was replaced with Ö on Icelandic typewriters, so '1' and '0' had to be typed as 'l' and 'O'. The method I recall for typing a bang was "acute, period". Not a pretty bang, but faster than "apos, backspace, period".