Red, Purple, Orange and Violet Proteins (IMAGE) Lomonosov Moscow State University Caption "Cover art" for this article reminds of the cover of the album "The Dark Side of the Moon" by Pink Floyd. It shows how red, purple, orange and violet proteins can be obtained from a colorless protein and one type of a carotenoid. Credit Eugene Maksimov Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.