What word, or phrase, do chemists use to describe the color saturation of a solution? Outside of chemistry, I've used the word saturation to talk about how blue (or how green, red, etc.) something is. In the lab that I'm writing, I have three undesirable options: 


use saturation and risk ambiguity with the other sense of the word (I could include a footnote that specifies the intended sense of the word; however, my experience has taught me that TA's rarely read footnotes.),
use an awkward construction (e.g. the degree/amount of blue exhibited by the solution), or
use an unusual term or a neologism (i.e. blueness).


None of those options are especially appealing. 

Is there a word that chemists use to talk about how blue (or how green, etc.) a solution is?
Using a spectrometer, you could accurately measure the degree to which light is absorbed by a solution ("absorbance" or "optical density") at a certain wavelength, and in a cell of certain dimensions. So, if you had a blue dye dissolved in water (which might appear blue because it primarily absorbs orange light), the absorbance (measured using orange wavelengths of light) would be proportional to the concentration of dye in water.