The absorbance at 700 nm can be used as a measure of turbidity or
haze. This is a measurement of the scattering of light by the suspended
solid particles. Increased haze will result in higher absorbance readings;
calibration curves for turbidity measurement are usually not
linear,however.
Browning is often expressed in terms of absorbance units at the
shorter wavelengths of the visible spectrum; 420, 440, 450, and 490 nm have all been used. We make our measurements at 420 nm as this is a
widely adopted practice