> Please do not mix colour and contrast. > > A well designed colour map which also respects contrasts might > perfectly work either with colours or in black and white.
Emphasis on *might*! I assume that you mean contrast in lightness, which was what I meant as well. Contrast can mean different things like the contrast in lightness/luminosity or the contrast between colors. You can have a shade of red and one of green that for normalsighted people obviously are different (because of color contrast), but are so similar in luminosity that in greyscale there would be no difference (no lightness/luminosity contrast). With color you have three parameters (RGB, CMY, HSL, Lab, etc.). Colorblindnesses reduce this to two (one color is deficient or missing, the others remain). Greyscale to one (Lightness). This is important when you want people to be able to identify features, not just make out their shapes in contrast to a background. If you restrict yourself to lightness contrast then you are limited to ~5 shades per similarly shaped feature (eg. "points" or "lines"). Add color and you have a multitude of that. CVD affected people can see lightness differences just fine and using that is key to CVD safe design. A map that works in greyscale will work for any color vision deficiency, that's the nice thing about it. But you can design a map that works for CVD affected people and fails in greyscale. I kinda lost my train of thought mid-way through but I hope you get what I am saying. Cheers, Hannes _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
