This page has a series of pictures of rainbows. The Niagara River goes south to north. If you are on the American side in the morning, you'll see rainbows. You'll see rainbows on the Canadian side in the afternoon. There is a brightness on these pictures. Rainbows, of course, are created when light is caught by water hanging in the air, so where there isn't a rainbow, the water droplets catch the light and make the rest of the picture brighter. And it appears that this effect occurs a lot below the rainbows.
A rainbow - 2 pictures combined
A rainbow - 2 pictures combined
A double rainbow - 3 pictures combined. If there is a double rainbow, it is a reflection of the main one. So the colors are reversed.
A double rainbow - 2 pictures combined.
