Something which came up in work today was a discussion about contrast standards and responsive web design.
Do we need to consider different standards regarding contrast once we start thinking about users beyond the desktop?
The WCAG guidelines provide guidence on contrast. At the BBC we aim for AAA compliance but will take AA when AAA is not possible for some reason. However, when considering responsive design (sepecifically mobile) i am increasingly thinking that going for the higher contrast standard is a good thing.
Typically mobiles and tablets tend to have quite shiny screens. This is great for making colors pop but introduces issues around glare and brightness. A shiny screen such as the iPhone uses a powerful backlight in order to reduce reflections and glare. Even then sometimes (direct sunlight, brightness turned down) the screen can be hard to read.
Try turning the brightness on your phone or tablet way down and then using it in different places and at different times. While the low brightness works great in the dark evening, the following morning walking outside it renders the device unusable.
Using higher contrast helps to reduce this issue and keep the site more usable more of the time.
(Photo from: AnandTech iPhone 4 review)