Text type principles

1. Type is (mostly) not graphic design...
a. ... while the choice and setting of display type is more or less graphic design, display type is 90 percent graphic, text type is 90 semantic communication...
b. ... and 90 percent of type is text type...
c. ... but blocks of text type are design elements...
d. ... although text type, even in blocks, is not a design element when you are reading it, which brings us to item 2....

2. Text type is meant to be read. Being looked at is a functionally secondary, if chronologically primary, function. That is, people see and look at text type before they decide to read it or not, so....
a. ... type must look readable. If it doesn’t, people won't even try to read it.
b. ... type must be readable. Or people who have been led to read it will give up. What characters look like is not very important. How they work is. And how they work is dependent on many things, and the typeface that the words are set in is unlikely to be an important element in this.

3. Given that typeface is reasonably conventional in terms of form, weight, and proportion, the choice of typeface is less important than....
a. ... its relationship to the context and other design elements. This includes placement, proximity to other elements, and visual weight of the block of type.
b. ... its line length. That is, it must be neither too short nor too long
c. ... its leading, which will depend on the line length and x-height of the typeface.
All these qualities may be estimated using logic, but reading the text is the only way to test its success.

4. Display type is fundamentally different from text type. It often does not have to be particularly legible, its appearance is central to its success. As such...
a. ... its form and expression should be carefully considered.
b. ... typefaces that make good text faces are unlikely to be the best display faces. In former times, display faces of the same typeface family had different forms, proportions, and interletter relationships than text faces. Few typefaces these days have different cuts for display and text types, but it is worth seeking out those that do.


and some smaller ones...

5. For all most every single typographical purpose, x-height is more important than point size. The x-height not only influences correct leading more than point size (see 3c), it effectively determines how many characters fit in a given space. Proposing to use a face with a large x-height in order to save space by using a small point size is an exercise in futility.

6. Text set in serifs is most successfully set in typefaces classified as Transitional or Old Style. Typefaces which fit the Modern classification are usually to light and contrasting. Sans serif text may well be a better choice, as long as it doesn't stray too far from what a reader is expecting to see.

7. Really looking at the type and reading the type will be a big help. I'll probably come back and add more to this when the mood strikes me.