Hi Dan

As it says in the article, such contractual small print is only unreadable because the originator doesn't want the end-user to read it. Other instances of small print can be perfectly readable; the x-height of the body type in the following image is about .6mm, and it was photographically reduced from a larger set size to get it down to this (‘A Book is Made’ printed by Jarrold & Sons, Norwich, UK for an exhibition by the Federation of Master Printers in the 1980s). Apologies for the picture quality.