The Professional Look – Part X
The Professional Look, The Complete Guide to Desktop Publishing, is a book I co-authored with Scott Tilden in 1991. Each Thursday I post an excerpt from the chapter I wrote about typography. Many of you dye-subbers also design some of the graphics you print, which includes setting type. Hopefully these posts will give you new insights into typography. Click here for my previous post.
Paragraph indents
While we’re talking about body copy, here’s another bit of free advice: Indent your paragraphs.
Some styles call for flush paragraphs — no indents. Some designers think it looks cleaner.
Maybe. But it does something else, too. It cuts reading speed by 7 percent.
Some designers argue that the first paragraph shouldn’t be indented because it aligns flush left with a headline above it.
We guess that’s OK. But then we see the technique done when the headline above it is centered. That’s really confusing.
Our counsel: Indent paragraphs roughly one pica. (For purists, indent paragraphs one em, which is the type size; e.g., 12 points for 12-point type, 10 points for 10-point type, etc.)
Saccadic rhythms: Line length
Research studies show that when we read our eyes move in what are called saccadic jumps, focusing on a small group of words for about a quarter of a second — until we understand — then moving to the next group. We continue this way until we’re done. Type set too wide forces the eye to work extra hard to track from the end of one line to the beginning of the next. Even when the eye can scan along the baseline of serif type, there’s a good chance the eye will get lost.
Type set too narrow forces the eye to spend almost as much time jumping from the end of one line to the beginning of the next as it does actually scanning typeset words. Too-narrow columns interrupt natural sentence flow, slowing reading speed and reducing comprehension.
Optimal line length depends upon type design and size. For example, one study of 10-point type conducted at University of Minnesota showed an 18.9-pica line to be optimal. Subjects read a 13.9-pica line about 7 percent more slowly, and they read a 43.9-pica line 11.4 percent more slowly.
In general, choose a maximum line width for body copy that, when measured in picas, will be no more than twice the size of the type when measured in points.
In short: Twice the point size in picas.
Typographers usually combine point size, line spacing and line length of type into one specification.
Example: ”Set 10 on 11 by 20 picas” means use 10-point type with one additional point of line spacing set on a 20-pica line length. It’s often written in shorthand form as: 10 /11 x 20.
Next week: Type alignment
Tags: indents, line length, Reading speed
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