Following the flow of a document can be difficult when the columns are either too wide or narrow. However, you can't determine column width without considering type size and leading.
With narrow columns, for instance, the eye scans down the page very efficiently, unless the type size is too large. A 12-point type in a narrow column will result in fewer words per line. On average, try to fit at least five to fifteen words per line. Create a few templates, compare them side by side, and then ask yourself these questions:
- How efficiently do your eyes scan the page?
- Does the amount of white space between words and lines make reading easier or harder?
- Do you find the number of hyphenated words distracting?
- Do the lines of text seem either too short or too long?
- Do your eyes get lost looking for the next line, or do they move easily down the page?