rainbow spectrum:colors is the first artbook by Toaru Majutsu no Index illustrator Kiyotaka Haimura and was released on February 28, 2011. It contains a collection of art from Haimura's light novel illustrations. The art book incorporates both color pieces and monochrome works in chronological order from Toaru Majutsu no Index, with shorter sections for other works like Maid DEKA and Sprite Spiegel. It also includes an interview, a tutorial, and an exclusive original short story written by Kamachi Kazuma "Toaru Majutsu no Index SS: Love Letter Competition".