is there guidance for the use of color for body text?
in Stop Stealing Sheep, Spiekermann uses red for type in the sidebars. i believe the thinking goes, it's ok to use pure hues when there's only a small amount of text.
doing testing, contrast is important -- if there's not enough, it's hard to read, thus black on white is good for this reason.
But is black on white an artefact of the printing press? color paper being more expensive, so white -- or off-white -- paper is often used for cost reasons?
the Financial Times is counter to this. they print on salmon pink stock, with black text. and it needs to be readable -- there's dense information with stock prices.
Modernist posters are another example, with an array of colors: both text and background. but this is a different situation. it's larger display type. i'm thinking specifically for long form writing, blog posts, books, and magazines.