I was wondering what point size of type was being used in the book where place is Vicenza mentioned in the previous post.
I considered the following page.
http://special-1.bl.uk/treasures/festivalbooks/pageview.aspx?strFest=0171&strPage=003
I clicked on the page in order to get a larger image.
There is a block of 20 lines of text on the page.
Using the centimetre scale down the side of the image, and estimating, the top of the top line of the block of 20 lines is at about 5.1 cm on the scale and the bottom of the lowest line of the block is at about 15.3 cm on the scale. So 20 lines of text and 19 lines of leading between them, if any leading is being used, takes about 10.2 cm of page depth. Is leading being used? The tail of the q in the first line of the block of 20 lines seems to go down to almost the level of the top of a long s and the N in the line below it. The tail of the q in the fifth line of the block seems to go down to almost the level of the top of the M in the line below it. I wonder if leading was used at this time in printing history?
http://en.wikipedia.org/wiki/Leading
The calculation that follows is as if leading was not used for the particular setting of text.
In English metal type printing in the 20th Century, there were 72 points to the inch. The point size of the font was measured as the vertical height on the page of the metal stem of the item of type: this measuring going from above the top of b to below the tail of q. In using fonts in Microsoft Windows, point size is above the baseline with descenders not counting in the point size calculation.
The 20 lines of text in the example here being studied take up about 10.2 cm of page depth. Using Microsoft Calculator, 10.2 cm is 289.13385826771653543307086614173 points (=72 * (10.2/2.54)), which for 20 lines of text is a point size of just under 14.5 points.
However, bearing in mind the experimental error in reading the 5.1 cm measurement and the 15.3 measurement and the doubling of the experimental error by subtracting one from the other, bounds of 10.0 cm and 10.4 cm for the measurement seem reasonable, which gives a range from 14.17 points to 14.74 points. I wonder what it really was? Maybe some direct proportion of a unit of measurement of that place and time, or maybe just a size which was used for some other reason?
Studying the illustration leads me to think that if the text were being set on a computer so as to achieve the same size effect as the original, then a computer point size of about two-thirds of the metal type point size would be needed, something like 9.6 point.
Whether the size of type used in the book is a consistent size used in various books in various places or whether it is a local size is an interesting question which needs further study.
William Overington
9 June 2008