Lee Wilson writes in Sourceable that we should pay more attention to luminance contrast. But what is this and how do you measure it? The International Standard gives a technical definition. The non-technical explanation is the contrast of the light reflected on one surface compared with that of another, adjoining or adjacent surface. For example the contrast between the kitchen bench and the cupboard below and the wall behind. So why do we need such contrast? Not everyone has perfect vision, colour discrimination, or visual perception. Contrasts provide good visual cues and create greater safety especially in areas like the kitchen and bathroom. Lee Wilson lists the many things in and around the home and public buildings that need such contrast in this Sourceable article. Wilson explains in more detail everyday items that we might not think of: coat hooks, locker handles, buttons, switches, toilet seats, floors/walls, and more.
You can also read Measuring up for luminance contrast for more information on the topic.