Whats a color that can be seen from far distances?

Question

like on a sign besides black!

Answer 1

Color is how we our brain interprets light as it enters our eye(s). All color, then, travels at the speed of light.  How far away light you can see depends on it's brightness and magnitude, not it's color.  

So, I would say, the best thing to make a sign that can be seen a great distance, isn't to make it any specific color, but to have it either shine brighter or reflect more light than the signs around it.  Size would obviously play a small role in this as well, if it's too small, you're not going to know it's a sign from, say, two miles away.

As others have pointed out, color will come into play as far as making such a sign "eye catching" or noticeable.  

Answer 2

Well i'm not sure but, you know in the morning how the sky is red.  Well i think its because out of all the colors in the spectrum, red is the one that travels the farthest.  So it beats everything else, and later in the day when the sun is closer and everything catches up it appears white.  So im pretty sure this applies for our sight, so red would probably be good for a sign. Hmm, is that why stop signs are red?

Answer 3

Green is the color that appears brightest to the human eye. If the green paint were fluorescent, It would absorb uv rays and emit even more light, making it brighter.

Answer 4

Red

Answer 5

For signs (and fire hydrants) the colors most likely to catch the eye are yellow, white, and red.

Edit:

You can do a google search for "colors that catch the eye" and find a study that has been done on it as the first result.