Yellow
Yellow has never seemed like much of a colour to me. It's more like off-white than a separate colour. I want to describe it as a dark white, but at the same time as a bright white. Are dark and bright opposites? I don't think so, because light blue is not bright; but I'm not really sure what bright means, unless it's perhaps "reflective." This brings me to the question of what distinguishes yellow from gold (and grey from silver). I remembering wondering about this when I was a kid, because Crayola's 64-pack had separate colours for yellow and gold, but I couldn't figure out what mixture of paints would reproduce gold. The trick, I realized, was that gold-coloured crayons had a sparkly element in them that clearly distinguished them from yellow; ditto for silver vs. grey. In practice, gold seems to be a little darker than pure yellow, but that doesn't stop people from describing blond hair as "golden." Yellow is one of the three pr...