Biological pigment symbiosis Trididemnum solidum, their colors are different depending on the light regime in which they live. The colonies that are exposed to full sunlight are heavily calcified, thicker, and are white. In contrast the colonies that live in shaded areas have more phycoerythrin (pigment that absorbs green) in comparison to phycocyanin (pigment that absorbs red), thinner, and are purple. The purple color in the shaded colonies are mainly due to the phycobilin pigment of the algae, meaning the variation of exposure in light changes the colors of these colonies. Aposematism is the warning coloration to signal potential predators to stay
Terry Pratchett's The Colour of Magic programming at Sky One, also appears as the Alchemist. A teaser trailer, released in late February 2008, featured principal cast members, including Rincewind, Twoflower, Trymon and the Arch-Astronomer of Krull, attempting to describe octarine, the 'colour of magic'. The teaser concludes with the film's tagline: "a pigment of your imagination". Two more trailers were released in March 2008, containing a more complete synopsis, with narration by Brian Cox. The trailers formed part of a multimillion-dollar advertising campaign in partnership with Amazon.com and Borders Books. In addition to conventional adverts in national newspapers and banner ads on sites including MSN.com and