Usability. UX and UI design without defining and setting usability goals defined by Web Content Accessibility Guidelines (WCAG) standards is a slippery slope into a world of hurt for you and your potential user.
One of the biggest failures in UI design is when there is not enough contrast between the type and the background color of the component it is on. The background for type be a button, a nav bar, the content area... essentially anywhere or in any form type is displayed. Not only can it make for a not-so-great to impossible experience for users especially if they have any type of visual impairment, but it can bring legal problems to developers and businesses.
As a graphic designer working in the industry of interactive design, it is important to learn about Web Content Accessibility Guidelines (WCAG) and how they should influence design decisions in the craftsmanship of user interface graphics.
One of my favorite tools out there to check if the contrast of my UI components will pass accessibility are contrast checker apps. There are many web apps and mobile apps out there for this purpose. Take a look at this example, I wanted to test the contrast usability of this button color scheme combo:
So I sampled the color of the text and the background color with an eyedropper tool to get the numerical value of each color and then popped each color value into Userway.com's nifty contrast checker web application.
Not only does it tell me that this particular turquoise and yellow color combo fails for enough contrasts it also supports its rating with more visual examples that automatically produce the resulting contrast ratio.
As a UX / UI graphic designer this is one of the many areas of usability that need to be researched to make smart design decisions. The success and longevity of interactive products must take into account the behavioral and functional aspects of the experience. The first place to get that wrong is with poor contrast. Designing for usability for a variety of users including the visually and or hearing impaired is an essential skill for an interactive digital product designer. This U, for usability, plays a major role in the success of UX / UI projects.