[Tex2002ans]

Originally Posted by hobnail

Old style numerals have decenders, so the 9 is like a p.

[... On] my body tag [I use] "font-variant: common-ligatures oldstyle-nums proportional-nums;" and for h1, h2, h3, h4 it's "font-variant: common-ligatures lining-nums proportional-nums;" [...]

I was also reading through the CSS3 Fonts Specs on "font-variant-numeric" and saw they have a nice comparison table showing differences between Proportional/Tabular + Lining/Old-Style numbers.

Originally Posted by Tex2002ans

And OCR definitely trips up on books with old-style numbers, so it's a very common error to look for:

I always do a Regex+Spellcheck pass for O/o or l/I next to a number (I942 -> 1942). And 1,ooo -> 1,000 is pretty common too.

Aaaand it comes up today!

The book scan in:

"How to handle images in books while doing OCR of books?"

was published in 1918.* Lots of tables and numbers, all in Old-Style:



"Ist July"
"IO July"
"IOO"
"I,OOO"

It has 'em all!

* I mean, I9I8.