this is by no means a convention, something i cooked up myself because i deal with this issue frequently making GUIs



at least it lets you know how much of either end of the scale is indicernible with your current settings. most of my guis tend to be light colours that blast people's eyes.. the only people i know who use settings like mine are also code oriented.

you're obviously not a novice, and it's something that most people never seem to consider. the only way i've been able to get a feel for 'median' settings is end user comments, other peoples' material.. i'd go crazy sitting in front of most people's monitors for more than a few minutes