What's the noun for yellownesses? Here's the word you're looking for.
yellow
(US) The intermediate light in a set of three traffic lights, the illumination of which indicates that drivers should stop short of the intersection if it is safe to do so.
(snooker) One of the colour balls used in snooker, with a value of 2 points.
(pocket billiards) One of two groups of object balls, or a ball from that group, as used in the principally British version of pool that makes use of unnumbered balls (the (yellow(s) and red(s)); contrast stripes and solids in the originally American version with numbered balls).
“The liver was softer than natural, and exhibited a notable yellowishness in the centre of the acini.”
“I know your pooch's urine has an incredibly artistic yellowishness to it, and the muscle definition when he lifts his leg is Shwarzenegger-like, but I'm eating my freakin' lunch and don't want to see it.”