Color Shifting Flakes are responsible for those cars, cell phones, clothing, and 65 of the world's currencies including all U.S. bills of over $10 that change colors depending on the angle at which you view them. Not only can these look unbelievably cool, but the technology behind them is quite interesting. The products have been painted with a substance that isn't actually paint, but a suspension of micron sized Flakes in a liquid chosen for it's adhesive properties, so it will stick like paint. The Flakes are between 12 and 35 microns big and only make up 2 to 5 percent (weight based) of the substance. This still means a huge number of flakes as they weigh very, very little. The liquid serves no other purpose, except that it should be transparent in order for the Flakes to function correctly.
Color Shifting relys on a totally different system then regular paint, that of light interference. Take a leaf, it is green because it absorbs all the light but green, which it reflects. That is absorption color. Now take a bubble or the film on the surface of a body of water, they create color because they directly interact and interfere with the light waves, amplifying some waves and dulling others to make the light you see. This is interference color. The Flake is a small slice of reflective core material, which is coated with several layers of film designed and created by OCLI, another JDS Uniphase subsidiary, that form a light interference structure, usually 5 layers of film. When light passes through the films at an angle, the wavelengths of the light are changed, the light reflects off the core, then is changed again by the films on the way out. If there is no angle however, then the light passes straight through and only reflects the core color. The wavelength changes are controlled by changing the thickness of the films. The reflected color is determined by the angle the light enters the flake, the depth of the films it must pass through, and the angle at which you view the flake. A layer's thickness is measured in microns, and the layer thickness must be uniform at the atomic level across the whole flake to properly function.
Making the Flakes involves electron beam deposition, which I know nothing about. But I know the equipment is very expensive, so the only people who sell the Flakes are Flex Products, which is a JDS Uniphase company, and the Nittetsu Mining Company of Japan. However, all the products you see will be of Flex Products ChromaFlair line, as apparently nobody likes the stuff from Nittetsu. Flex Products does not actually sell any paints or colors of any kind. They manufacture the Flakes, then sell them to manufacturers for use in their products. Manufacturers achieve custom colors by specifying the core materials and films used to manufacture the Flakes they buy. The Flakes can be customized to shift to more than 2 colors and also mixed with regular paints or other materials to enhance them. Car manufacturers tend to go all out and create Flakes that shift across almost the whole spectrum of visible light.
Color shifting paints are available from several different companies, so you can get the color shift you want and paint away! ChromoFlair paints are treated the same as regular paints, and last just as long as they contain no organic components. When you use paints, you can mix them with anything you want. Remember! Just like normal paints!
Below is a list of companies that sell ChromaFlair paints and the product names they use.
http://sol.sci.uop.edu/~jfalward/lightinterference/lightinterference.html
http://www.nittetsukou.co.jp/jisei/index.html?1,shift-e.html
http://www.colorshift.com
http://www.ocli.com/
My interest in this stuff was piqued when I got the idea that I wanted to color my hair with color shifting dye. I talked to cmyr about it and found out that such a thing actually exists, then found out that it doesn't exist in the form of a hair dye. So whenever I can get my hands on some, I'm going to have a (trustworthy) friend color my hair with spraypaint. I'm thinking a dark shift, many subtle colors, but has a small bright streak in the shift that flashes out at certain viewing angles.