Black and White, being high contrast, are definately the best. In fairly dimly lit cockpits, some colours/colors make for more difficult reading. Yellow is probably the worst (why did Airbus have to have a Yellow Hydraulic system for heaven's sake, why not Red?).
Coloured pages can be beneficial to safety in a well lit cockpit environment, e.g. pre-flight. Our Airport Analysis pages have different colours for Dry/Wet/Contaminated Runways etc., which helps to avoid choosing the wrong data.
Of interest, a crash investigation in Australia some years ago cited type font as a possible cause for confusion. Courier was the "suspect" font, and investigation suggested that Arial is the font of choice in preparing Operations Manuals.
Regards,
Old Smokey