Colors strength is defined as its Tinctorial Power, KO.56.
Tinctorial power is the absorbance of a 0.1% weight / volume
solution. It is measured through a 1 cm light path at a wavelength
of 560 nanometers (nm). The weight/ volume is measured using a high
quality spectrophotometer. Higher the value of the absorbance,
darker is the Caramel Color.
Color tone is also an important factor. The color tone is defined
by the Hue Index that is the measurement of the color hue or red
characteristics of the Caramel Color, a function of the absorbance
at 510 and 610 nm. As a fact, the higher the Tinctorial Power, lower
will be the Hue Index and the lower will be the red tones.