I'm color blind and frequently turn off colors on webpages. Try this bookmarklet to remove the colors to get a standard black on white page while preserving (most) everything else.

javascript:(function(){var newSS, styles='* { background: white ! important; color: black !important } :link, :link * { color: #0000EE !important } :visited, :visited * { color: #551A8B !important }'; if(document.createStyleSheet) { document.createStyleSheet("javascript:'"+styles+"'"); } else { newSS=document.createElement('link'); newSS.rel='stylesheet'; newSS.href='data:text/css,'+escape(styles); document.getElementsByTagName("head")[0].appendChild(newSS); } })();