Rainbow Books
The Rainbow Books are a collection of CD format specifications. Section::::"Orange Book" (1990). Orange is a reference to the fact that red and yellow mix to orange. This correlates with the fact that CD-R and CD-RW are capable of audio ("Red") and data ("Yellow"); although other colors (other CD standards) that do not mix are capable of being burned onto the physical medium. "Orange Book" also introduced the standard for multisession writing. Section::::"Scarlet Book" (1999). Scarlet color of this book is a reference to the Red Book, which defines original CDDA.