There were rarely any colour in Maus as it relied on the texture and shading to show depth and character. Spiegelman wanted the effect and immediate quirk of the lines, he explains why it's in the original format the way it's draw, because he wanted the book to resemble a journal with a sense of intimacy, and how easily accessible it is. Spiegelman would say that he would use stationary tools to make his comics, for he was good at writing so he treated his pages more as a manuscript. Spiegelman did try using scratch board illustration for the visual surface, however it distracted from the story.The only colour shown was on the covers were we can only see how the characters look in colour, with the title in being a bold red, and the Swastika logo in the background.
"Why Mice? by Art Spiegelman." Why Mice? by Art Spiegelman. N.p., 20 Oct. 2011. Web. 30 Nov. 2015. <http://www.nybooks.com/blogs/nyrblog/2011/oct/20/why-mice/>.