Qualia Of Red

Qualia are the distinct raw sensations of particular experiences that make up our consciousness.  An example I was presented in the book I'm reading by Christof Koch says:  "The quale of the color red is what is common to such disparate percepts as seeing a red sunset, the red flag of China, arterial blood, a ruby gemstone, and Homer's wine-dark sea.  The common denominator to all these subjective states is 'redness'."