For all its transcendental appeals, art has always been inextricably grounded in the material realities of its production, an entwinement most evident in the intriguing history of artists' colours. Focusing in on painting's primary trio of red, yellow, and blue, Philip Ball explores the science and stories behind the pigments, from the red ochre of Lascaux to Yves Klein's blue.

Humans can't see UV light, but birds can. By combining spectral light with UV, researchers proved that birds can differentiate between those colors. This means that when the birds look at objects we can see as spectral light, they are likely seeing many more colors because that fourth cone gives the ability to see more color combinations.

The actual study is here.

The reason why purple and violet look similar to us is because they stimulate our cones in a similar way, but most other animals don’t share the same types of cones and “post-processing”. This means that to other animals, purple and violet may look completely different!

Now imagine a violet flower petal with a purple pattern on it. Depending on the particular shades, this pattern might be completely invisible to us, while many other animals could see it as clearly as we can see an orange pattern on green background.

It turns out that if all the stars and all the planets in all the galaxies were before you in a terrifying, brilliant, impossible box, the color would you see (while no doubt experiencing a transcendent feeling of oneness) is the most boring color in the world.

How well do you see color? FACT: 1 out of 255 women and 1 out of 12 men have some form of color vision deficiency. Take the online color challenge, based on the Farnsworth Munsell 100 Hue Test.

We extracted the colors from 10 million Creative Commons images on Flickr. Search this collection by color. Addictive and very likely the best color search engine in the world*!

Pick a starting color and get complements, triads, tetrads, etc., calculated automatically.

With the test images on these pages, you can easily adjust the settings of your monitor to get the best possible picture quality. Additionally, there are a number of test images that can help you to judge the image quality of a monitor. You can check the images on this webpage or put them on a usb stick and try them in the computer store like I did when I created these test patterns. These test images are much more revealing regarding monitor shortcomings than ordinary photographs.

Colorifer is a wrapper to run program and colorize it's output. [sic]