Respiratory pigment Respiratory pigment A respiratory pigment is a molecule, such as hemoglobin in humans and other vertebrates, that increases the oxygen-carrying capacity of the blood. The four most common invertebrate respiratory pigments are hemoglobin, hemocyanin, hemerythrin and chlorocruorin. Hemoglobin is bright red when oxygenated, and dark red(purplish) when deoxygenated, oxygenated hemocyanin is blue in colour, deoxygenated it is almost colourless. Oxygenated chlorocruorin turns from green to red, whereas oxygenated hemerythrin is a violet to pink colour and colourless when deoxygenated. Any of various coloured conjugated proteins, such as hemoglobin, occur in living organisms and function in oxygen transfer in cellular respiration.
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