Seeing the page
For at least 2000 year we have known that people can see close objects less clearly as they age. For example, the apostle Paul, who was clearly able to both read and write, dictated his letters to a scribe but often signed them in his own hand (1 Corinthians 16:21, Colossians 4:18, 2 Thessalonians 3:17, and Philemon 1:19). Paul was around fifty years old when he wrote these letters, and (in common with most men and women of that age, then and now) probably could not see clearly anything closer than three to six feet from his eyes, unless he wore reading glasses.
But reading glasses were not invented until around 1286 AD, when they appeared in Italy. Early manuscripts, from dates before the invention of reading glasses, tended to be written in relatively large letters, in a style which allowed them to be read easily, even when slightly blurred. But even after glasses became available, large letters drawn with thick lines continued to be used. Glasses were expensive, clumsy, and not particularly good quality.
The same style of lettering continued after the invention of printing. The Gutenberg Bible, the first printed book, had 40 to 42 lines of type on a page on a page 445 mm (17.5 in) high. A typical modern Bible has 65 lines of type on 234 mm (9.2 in). That’s a big change in type size. When did it happen, and why?
The type used in early printing is called blackletter for quite obvious reasons.
Two blackletter typefaces are Antiqua and Fraktur, both of which have letters characterized by thick lines for all essential parts of each letter.
In 1757 John Baskerville introduced a new typeface, which he claimed to be more legible than others.
To the modern eye, there is little doubt: it is more legible. But let’s see how it stands up to the view someone with presbyopia will see of this typeface, by blurring it a little, along with a blackletter typeface.
There may seem to be little to choose between the two which is clearer, but look again. The letter e in the Baskerville font could easily be a c.
So what happened around 1757 which made John Baskerville think this was more legible?
I haven’t seen this suggested anywhere, but it seems to me obvious. Reading glasses became easier to use. During the preceding fifty year so-called temple spectacles, ones which actually stayed in place, thanks to legs pressing on the reader’s temples, were invented and perfected. Reading glasses now became comfortable and stable, as well as available. Baskerville’s printing of the Bible using his typeface in 1763 helped spread the use of more modern typefaces and the disuse of the old blackletter type. In English, anyway. German printers continued to use blackletter type until after World War I.