A couple of centuries ago I enrolled in journalism school and, after the first year, got out pronto. Well, not "got out"--it was so boring that I simply forgot about journalism and took nothing but liberal arts courses from then on. But one journalism course I loved was basic typography: we were led into a basement shop and turned loose on California job cases, printers' knots, solid-brass "sticks" and pica gauges, and clamshell presses. In short, it was a too-short course on setting type by hand, and I loved it. One thing that has stuck with me all these years is the rule or notion that for each size of type there is an ideal or maximum column width beyond which legibility suffers. I used to have a sheet that gave the ideal width for each of a dozen or so fairly common type sizes, and I will be grateful to anyone who can steer me to a replacement.
I mention this because it seems to me to be be common magazine practice nowadays to set type too wide. For example, in the re-designed NYTimes Sunday Magazine, columns in the same-size type (looks like 9-point) are sometimes 15 picas wide and other times 23. The latter are (to me) far less readable than the former. I'm convinced that 23 picas is significantly beyond the "ideal" width, and I want to confirm my impression.
Any help will be appreciated.
(FYI, I liked proofreading, too, and in my professional life once caught a wrong-font period on an upside-down mechanical. I did not, however, find any use for my skill in hadset type. By the time I graduated the publishing world had graduated too, into the new world of high tech: Linotype machines!)