Readability & Legibility
Legibility: is how clearly you see each separate letterform.
- The perception of a letter is based on the form and counterform relationships.
- counterforms, or the negative space, are equally as important.
Readability: is how easily your eye moves across the page.
Interline & Interletter Spacing
Interline spacing is the spacing between two lines, you adjust this with leading. Interletter spacing is the spacing between two letters, you adjust this with kerning.
- If you have larger type in color increase the interline spacing.
- Sans serif fonts need more interline spacing, serif fonts don’t.
- Generally, lines with less interline spacing are read more slowly than those with more interline spacing.
A few definitions —
Tracking: adjusting the interletter spacing between an entire word or line.
Set Solid: when text with a 12 point size has 12 point interline spacing.
Reverse Leading: when text with a 12 point size has a smaller point interline spacing, for this example anything less than 12 (generally means the text will overlap).
Margins are important for legibility. If your margins are too small, the readers’ eye will get tired. There should be 10-12 words or 60-70 characters per line.
In terms of typefaces, Helvetica and Univers are more legible than Futura because there’s more variation in their letterform.
- Text that is set entirely in capital letters is less legible because it creates a straight horizontal alignment and the letters seem to have a similar shape and size.
- Text with a variety of letter shapes, ascenders and descenders give the reader more variation and therefore, better perception.
There’s debate over whether serif or sans serif typefaces are more legible (many people say serif fonts have more character definition). However, both are equally legible as long as you add interline spacing to the sans serif typefaces.
- The optimum sizes of text type or body copy are 9-12 point.
- The optimum sizes for headlines and display type are 18-24 point.
Long copy should never be flushed right or justified.
- For certain reasons, justification can be used, but in terms of legibility flushed left or right is always best.
Magazines, books and newspapers usually indent for the beginning of each paragraph. In terms of typography, it is best not to do this. You can achieve the same effect by adding additional interline space between the paragraphs.
Type & Color
Black type on a white background and black type on a light gray background is highly legible.
In order to acheive appropriate contrast between type and a background, 3 color properties need to be considered:
- hue (specific name of a color)
- value (lightness or darkness of a color)
- saturation (intensity of a color)
- How these properties are balanced determines how legible it will be
- Highly saturated colors like blue and orange give the most hue contrast, but when used for the type and background the colors have a “dizzy effect” and compete in brightness, to fix this lighten either the type or the background.
- Analogous colors, or colors that are close to each other on the color wheel, typically have enough contrast without looking dizzy.