Page Tones: White, Black, and Gray
Unless a publication is in color, white, black, and gray are the only tones on the page. Blank areas comprise the white space, graphics the black, and text the gray.
The goal is to balance these tones on every page. For instance, too much white space can make it hard for readers to follow the flow of a document, and if you clutter the page with too many graphics, rules, and subheads, it will appear dark and busy, while the graying effect of a text-heavy page will discourage even the most interested readers.
Though each tone is equally important, they only have meaning only in relation to each other. White space is only useful if it's contrasted against the black or gray tones. Black tones only provide contrast if there is blank space and text on the page. Good designs balance the three tones together.