Why is type hight .918?

We have discussed this before, please see:

http://www.briarpress.org/15811

I think a likely possibility is that when ATF was formed from a disparate group of foundries with different heights-to-paper and body-size standards (although height to paper got standardized earlier) the largest number of them using the same numbers became the standard. Standardization was a slow process but necessary if competitors expected to sell type — different body sizes could be tolerated but different heights-to-paper made printing with mixed type impossible. In most industrial cases the largest group with the same standards becomes the default standard.

Bob

To my knowledge, there is no definitive answer to the genesis of type-height. I expect the truth is somewhere close to “Because that’s how high the blacksmith made the mold cavity.” I expect the earliest type sizes were similarly developed by their matrix engravers.
—
Michael Hurley
Titivilus Press
Memphis, TN

would you believe that when Jonas Gutenberg began casting type in Germany, he wanted to cast everything one (1) inch. And so he used the kings decreed value for an inch. Which just so happened to be .918 of what we all today call an inch. by the way there’s an interesting printing meuseum in the city of Lancaster Pennsylvania
run by the .918 club check us out if ever in Lancaster.

Actually I wouldn’t believe that. Early printing types varied between printers, as they were forced to make their own molds and matrices, and cast their own types. In the American Dictionary of Printing and Bookmaking, 1894, on page 556 in the entry on type making there is a diagram of tracings of types that were recovered from the river-bed of the Saone in France with the accompanying text:

“Type varied in height at the beginning from three-quarters of an inch to an inch and a half. It had no nick and its face had a long shoulder below… It perfectly agrees with a thin letter found in a book printed in Germany which was smashed upon the top of a page and remained there imbedded. An impression from the form while this condition lasted is still preserved and gives witness as to the shape of letters four hundred [now five] years ago.”

Nothing has survived from Gutenberg, so no one knows what his type was like in either size or composition, and anything on the subject is mere conjecture. The first book published on the subject was written more than 150 years after the beginning of printing from moveable types, and in those ensuing years there was no attempt at standardization, nor was there for centuries after.

EarlyTypeHeights.JPG

TypeAccident.jpg.JPG

According to this http://sizes.com/tools/type.htm, 0.918 was adopted in the US in 1886 as some kind of metric rounding - see web link - on 11/12th of an inch (0.9166 inch), and was adopted in Britain in 1898.
0.918 = 23.333mm, and in 1898 an British silver shilling was 24mm, so similar enough perhaps to drop into a layman’s explanation over here (both being ‘just under the inch’ (inch = 25.4mm), but of course the US had used dollars for over a hundred years by the time of standardisation.
(Reference for shilling diameter - http://www.silveragecoins.com/en/details.php?item=1404 )