Eli5: how were things like old books digitized for the internet? Did someone scan each page? Did they just re-type it word for word?

Question

I was thinking about public domain books and it got me wondering.

In: Technology

Answer 1

digital scans and captcha codes and OCR software.

Remember about a decade ago when all of captcha was “What word is this???” That was words that the digitizer wasnt sure about, so it was crowdsourced to everyone on the internet to figure out.