Icon Usage Guidelines
References
https://ia.net/topics/on-icons
https://uxmyths.com/post/715009009/myth-icons-enhance-usability
https://sympli.io/blog/when-you-should-and-shouldnt-use-icons/
https://archive.uie.com/brainsparks/2006/02/20/orbitz-cant-get-a-date/
https://www.nngroup.com/articles/icon-usability/
https://ux.stackexchange.com/a/5087
Summary
Naturally, you should use an icon when you don’t have enough space for a text label, but this isn’t always the best reason to use an icon. First you should consider creating space in other ways.
Many researchers have shown that icons are hard to memorize and are often highly inefficient. Icons are very difficult to get right and need a lot of testing. Icons add width and clutter, distract the user from the content of the app, and, contrary to intuition, do not necessarily help the user find an UI item better than a text label alone. It’s not worth it.
Even though icons can certainly make a design look more visually appealing, visual appeal doesn’t necessarily equal optimal user experience. They can be very distracting, especially when it isn’t clear what an icon represents, so use them with caution and minimise whenever you can.
While icons depict tangible objects fairly well, for anything abstract, icons rarely work well, since abstract things generally do not have any clear visual image. Icons are especially bad for actions, it’s hard to clearly show a process with a picture. We can eye-scan over icons faster than we can text, however images rarely give us the information we need.
Yes, icons are used all the time in toolbars for actions, but toolbars were intended for experts, and nonetheless users are frequently confused by them. Expert users will learn a set of icons (perhaps), but you will be surprised how long the learning curve is.
The research community has long demonstrated that people cannot remember the meaning of more than a small number of icons. The location of the icon is more important than the visual imagery. People remember where things are, not what they look like.
Always consider the reason for using icons, and never assume icons will enhance the user experience.
Use an icon only when it provides additional clarity or is necessary to draw attention to a UI element.
- Icons can save space over text, but at the price of recognition.
- Good icons can make the look of an app more pleasing, but it’s hard to get the right icons.
- Icons represents an object with a strong physical analog or a visual attribute work well.
- Icons can serve as bulletpoints and also for structuring content, e.g. file type icons.
- Don’t overuse them or use them for decoration.
Remember the best icon is a text label.
Icon Design Guidelines
Summary
Icons need to be recognizable by themselves, they need to illustrate the notion they represent clearly, and they need to work together with all other icons and notions you use, in context.
Use icons that people have seen and used before. Universally understood icons work well, i.e. home, print, close, play/pause, magnifying glass for search, etc.
A user’s understanding of an icon is based on previous experience. Remember that different cultures may interpret the same image in different ways.
Simplify icons for greater clarity and legibility. The best icons are simple shapes and pictograms that users can instantly identify. A distinct silhouette is the most important feature of an icon.
Make sure there’s enough contrast between states, like active versus inactive. Avoid using similar icons for different purposes or different icons for the same purpose.
Links
https://medium.com/bpxl-craft/10-essential-tips-for-user-interface-icons-e7d04b5988a5
https://www.designsystems.com/iconography-guide/
https://design.gitlab.com/product-foundations/iconography