The average human eye has three types of cone cells, each of which is sensitive to a different wavelength range of visible light. The difference in the relative signal from the three cones allows us to distinguish colors. Unfortunately, since these sensitivity ranges overlap, there are some combinations of signals from the cones that can't be created by light emitted from a real object. These are the so-called "imaginary colors". However, by selectively overstimulating one or more types of cone, we can still perceive these colors; this is the principle behind the Eclipse of Titan, an optical illusion which produces both a green and a cyan that don't otherwise appear in nature. (Similar effects can be seen in the Eclipses of Mars, Neptune, and Triton.) [more inside]
posted by Upton O'Good on May 10, 2010 - 64 comments

"What is the sound of color? We asked that question of 5 musicians. We assigned each musician a different color. They wrote 5 tracks. We gave the colors and tracks that inspired them to 5 directors." The Sound of Color contains the songs and videos that were created. The site and free downloads are only available through March 15. (Via Carolina Vigna-Marú) [more inside]
posted by madamjujujive on Feb 18, 2008 - 23 comments

The Blue Marble ... true color global imagery at 1km resolution.
posted by crunchland on Jul 19, 2003 - 14 comments

Blue man runs for Senate Stan Jones, the Libertarian candidate for U.S. Senate in Montana suffers from argyria, a condition in which the skin becomes stained a permanent shade of blue. How do you come down with it? You drink lots of colloidal silver. Jones started mixing his own shortly before Y2K to help boost his immune system in the antibiotic-short apocolypse he was sure was coming. No word if he is now engaged in weird behavior involving metal tubes.
posted by agaffin on Oct 3, 2002 - 27 comments