Da*, Da, DCRG
Color Difference of a sample compared to a target along the red/green axis. For a color other than red or green, this value indicates a shift in Hue. For example, a positive number indicates the sample is redder than the Target and a negative number indicates that a sample is greener that the Target.

Db*, Db, DCYB
Color Difference of a sample compared to a target along the red/green axis. For a color other than red or green, this value indicates a shift in Hue. For example, a positive number indicates the sample is more yellow than the Target and a negative number indicates that a sample is bluer that the Target.

DC*
CIELab Color Difference representing Metric Chroma difference. A positive number indicates the sample is more saturated than the Target and a negative value indicates the sample is less saturated than the Target.

DC*/SC (CMC Equation)
Metric Chroma difference. A positive number indicates the sample is more saturated than the Target and a negative value indicates the sample is less saturated than the Target.

DC
Chromaticity difference between a sample and Target with no indication of position relative to the Target in Color Space (used with FMC-II equation only).

DE*, DE
A number that calculated from any Color Difference equation, representing the total color difference.

DH*
CIELab Metric Hue difference. The neasure of metric Hue differnece calculated in CIELab units from the following equation
DH* = ((DE)² - (DL)² - (DC)²)^1/2

DH*/SH (CMC Equation)
The hue difference devided by the CMC hue weighting factor

DL*, DL
The difference in Lightness (or Darkness) between a sample and a Target. A positive number indicates the sample is lighter than the Target. A negative number indicates the sample is darker than the Target.

DL*/SL (CMC Equation)
Lightness difference devided by the MCM lightness weighting factor.

Fluorescent
The process by which electromagnetic radiation is absorbed at certain wavelengths and then re-emitted at other wavelengths

h
Represents hue angle in CIELab Color Space, reported in degrees. In CIELab Color Space, the Chromaticity of a color may be plotted as one point to the origin is known as Metric Chroma. The angle, h, that the Metric Chroma line makes with the a* axis is defined as hue angle. The hue angle is always measured in a counter clokwise direction from the (+) a* axis.