[texhax] Line width and 66 characters per line

[Dan Luecking]

On Wed, Aug 27, 2014, at 17:25 CEST, Jim Hefferon 
<<mailto:texhax%40tug.org?Subject=Re%3A%20%5Btexhax%5D%20Line%20width%20and%2066%20characters%20per%20line&In-Reply-To=%3C8E15C2BC0B63AD4AA20BF9F1C3947FC10139CFD0F0%40SMCEXMBX03.mikenet.smcvt.edu%3E>jhefferon 
at smcvt.edu>
wrote:

 >I've often heard that when laying out a document we should try to
 >set the line length so the number of characters per line comes out
 >close to 66.

I've heard that too, but my first hearing predates the existence
of personal typesetting software, so it really applied to a type-
writer. That is, to monospaced fonts with about 12 characters to
the inch, so this would give a width of 5.5in. This seems OK to
me, witness this email. It is unclear whether anyone ever re-
evaluated this advice after typesetting by the people became
common.

On the other hand, I just grabbed four random books off my book-
shelf, two are popularizations of science and two are a research
level books in math. Three of them adhere to the 66 character
standard and the fourth has an average of 75 characters per line.
All look perfectly reasonable on the page.

Maybe I am too imagination impaired, but I find it hard to judge
whether your examples are suitable when they have no margins. I
would need to see them with at least .5 inch margins (as exist
in the previously mentioned books from my shelf) in order to
judge.

Also the unreasonably large size for the section header seems to
make the other lines appear shorter. Too bad there is no similarly
well-known advice for title and heading fonts.

Finally, these samples have an unusually large amount of white
space (not unusual for math, but for books in general). That con-
tributes to the feeling that the page is too small. For math, with
  many displays, I would suggest that 72--78 characters to the line
might be a reasonable rule of thumb (6--6.5 inches on a typewriter).

Dan


Daniel H. Luecking
Department of Mathematical Sciences
Fayetteville, Arkansas
http://www-cs-faculty.stanford.edu/~knuth/iaq.html