black and white and blue all over

All the following words ultimately go back to PIE *bhel- ‘bright, shine, gleam, glitter; white’ English black, blank (French blanc ‘white’), blanch, blanket, bleach, blue (> *bhlē-wo-), flame, and flagrant; Old English blǣco ‘paleness, leprosy’, Latin flāvus ‘yellow, yellow-red, blond, red, golden’ (> *bhl̥ə-wo-). See IEW bhel- 118ff., bheleg- ‘shining’ 124, & bhleu-k- ‘burning’ 159. That’s quite a semantic spread there.