Projects/Usability/HIG/IconDesign

Purpose

Icons are pictorial representations of functions and objects, important not only for aesthetic reasons as part of the visual identity of a program, but also for utilitarian reasons as shorthand for conveying meaning that users perceive almost instantaneously. Well-designed icons improve the visual communication and strongly impact users' overall impression of visual design. Last but not least, icons are space-saving and improve usability by making programs, objects, and actions easier to identify, learn. Icon use should be consistent throughout the interface.

Guidelines

• Design icons with a small number of metaphors [1].
  • Apply metaphors only once (e.g. do not use a brush twice for different options).
  • Rethink conventionally used metaphors (e.g. the clipboard icon of paste).
  • Antiquated metaphors might work well (e.g. a floppy is not necessarily outdated to represent save).
  • Adjust the degree of abstractness according to familiarity of the metaphor.
  • Use arrows only if they can easily be related to spatial features such as Previous/Next in a sequence or Up/Down in a hierarchy. Avoid using arrows metaphorically (such as for Reply/Forward or Undo/Redo).
  • Attempt to use metaphors that are independent of language and culture.
  • Make icons simple.
• If an icon has important details at larger sizes, rather than simply scaling it down, create unique versions of the icon at smaller sizes. Critical details may become unrecognizable when scaled down.
• Avoid using text in icon designs; it may not scale well to smaller sizes.
• Icons of a similar type share a consistent visual language (mimetypes, folders, devices, etc.).
• Test your icon set on strength of association, discriminatory power, conspicuousness, and, if applicable, on accessibility.

Monochrome Icons

• Used for application toolbar actions, menus, and status and notifications. Also used for small (16x16) devices and places icons (folders, usb drives, etc.).
• Rely on a distinct shapes instead of fine details to distinguish between them.
• Color can be used for distinction (change of state, destructive actions, etc.).

Application icons

• Unique and easily recognizable.
• Have the widest variation of color and visual style to represent the visual identity of the application.
• When creating an system icon theme, respect trademarks by avoiding significant alterations to application icons.

Implementation

• For standard actions (back forward, open, save, refresh, etc.) use an icon from the platform-provided set. The KDE Platform 4.x uses the Oxygen icon set. Ask at the kde-artists mailing list to request addition of a specific item.
• http://websvn.kde.org/trunk/kdesupport/oxygen-icons/
• https://mail.kde.org/mailman/listinfo/kde-artists
• If you would like to request help designing icons unique to your application, you can ask for help on the KDE Visual Design Group Forum.

References

[1] http://user-prompt.com/semiotics-in-usability-guidelines-for-the-development-of-icon-metaphors/