Text & Character Attributes

While graphics are increasingly being used in displays, most information is still conveyed through text either in a standalone mode or to label symbols, icons, graphs, or other objects. How text is used in a visual display depends on the application. A self-paced, on-line course of instruction will contain much more text than a highway sign on a high speed freeway. Further, specialized displays for air traffic control, aircraft cockpits, or maintenance troubleshooting may use text very differently than either of these examples.

To incorporate text effectively in visual displays, the following character and text attributes must be considered:

• Contrast - Brightness contrast between character and background.
• Size - Height, height-to-width ratio, strokewidth-to-height ratio, character spacing, word/item spacing, and line spacing.
• Font - Character shape, presence or absence of serifs.
• Color - Choices for text, background, color-coding.

Selecting the appropriate character and text attributes depends on:

• User Population - Who will use the display? What are the user's vision characteristics: age, acuity, accommodation, color vision?
• Display Application - How will the display be used? What is its purpose? What information does the user need? How fast and in what form is this information needed? What are the expected ranges of viewing angle and viewing distance?
• Environment - What is the level and spectra of ambient illumination? Will the display be used in an office environment, an air traffic control tower, aircraft cockpit, maintenance area, or equipment shelter?