Photo a day: Colour

With a "u", they spell it. In French, you get two u's: couleur. Is a hue or a value or a shade or a wavelength more refined the more u's it has?
At work we add colors to an Excel table to mean things. Grey is just ok. Bright yellow screams for confirmation. Pink for unclassified variants, a paler shade of Red for Danger: Mutation. It's our way of adding an extra dimension to a flatland spreadsheet.
Red light: stop!
Green zone: safe.
Red cherry: eat.
Green apricot: wait.
Colors mean stuff - you just can't always tell what.
Trayvon: blood as red as yours.