2002/8/22. Harding ice field trail, Seward, Alaska. I've never seen a rainbow with such vivid color, especially violet. Could be the pristine air of Alaska. Nikon Coolpix 995 digital camera with a polarizer filter. Rainbow light is almost completely polarized, that is to say, if the polarizer filter is rotated 90 degrees, the rainbow would disappear. On the other hand, under the right angle all rainbow light passes but some ambient light is filtered out, so the contrast is enhanced.

Harding ice field trail, Alaska