For years I thought I had an idiosyncratic visual problem with mostly-white or mostly-light displays--headaches, loss of mental focus, etc. I used X's (horrible) preference "system" to set my world to black backgrounds. I had trouble using rio for long periods of time and thought about building my own with different colors.
Now it turns out that the "display brightness" problem I had was limited to CRT's, so maybe it was a flicker artifact. Due to years of habit I prefer dark-background displays, but I'm also giving rio's color scheme a chance to convert me. Dave Eckhardt
