how many columns?

[Cherlyn B Paul <paulc -at- BATTELLE -dot- ORG>]

          Kathleen Kuvinka asked if a two-column format saved space
          over a one-column format.

          No, because you sacrifice the space between the columns.
          And if the columns are right-justified, you sacrifice more
          space justifying two narrower columns than you would
          justifying one wider column.

          But--and this is a big but--please don't select a number of
          columns based on saving space.  (To explain:  take the
          space-saving directive to its logical extreme and you have a
          solid page of text...that no one would read!)

          In the paper
          publishing world--books, from which so many of our
          well-tested and reliable rules of thumb derive--the maximum
          column width is considered 28 picas, 30 if pressed.  A pica
          is about 1/6 inch, so this is a bit less than 5 inches.  The
          reason is that the eye, when moving from the right-end of
          one line to the left-start of the next, will start missing
          its target after traveling more than about 5 inches.  So
          readers will find themselves reading the same line twice, or
          skipping a line.

          As a reader, I find it equally disconcerting to have to jump
          a line every few words (i.e., a very narrow column).  As a
          writer, I do not like to see a thought I put effort into
          phrasing, being chopped up into a bunch of short lines...
          because I know the reader will have more trouble with it.
          By the same token, when writing phrases meant to capture
          attention, convey a topic at a glance, etc., I appreciate a
          short line, preferably with white space around it or perhaps
          some other appropriate design element nearby.

          (I don't know what sort of document you're designing,
          but...)  To help you with the others you mentioned who also
          have a part in this decision, I would emphasize that number
          of columns is only one part of design.  Start with a design
          that will convey this particular information best to these
          particular users; let the number of columns be whatever they
          be.

          Good luck!
          Cher Paul, paulc -at- battelle -dot- org