Usage of ‘blueness’ rather than ‘blue’

In some cases blue and blueness would seem to be the same. But in a sentence like "By selecting for a slightly different shape in the scales of the wing, scientists bred a population of brown butterflies into blueness" you can see that the quality of being blue is not quite the same as the name for the color blue.

Blueness could be used to discuss the relative amounts of blue in two pigments. "This one has a greater level of blueness that that one."

Blueness is probably more commonly used in cases where it refers to another meaning of blue besides color.

"I couldn't watch the entire act because of the sheer blueness of the jokes." "The blueness of the county was evident in the fact that you couldn't buy a beer at eight o'clock on a Saturday." "He wrote these dark songs when he was overwhelmed by blueness."