CIE-lab system (LHC)data interpretation

L: Lightness (Color strength)
- Positive: Weak
- Negative: Strong

C: Chromacity (saturation or dirtiness of the color)
- Positive: Clean
- Negative: Dirty

H: Hue (Color shade)
- Positive or negative difference depending on the selected color region.
(Refer to the chromacity circle)

First and foremost, it is important to always position the strength. To assist in the completion of this task, you can use a spectral tool that calculates the percentage of strength. A negative L could be translated as a strength percentage of 115% for example. This variable is vital as a color could appear cleaner, dirtier or of an altered hue if different than the established standard. For example, a blue that is stronger than the std will appear to be dirtier or more saturated and undeniably redder than what it is in reality. Color strength can be affected by the three following variables: The anilox volume used,the viscosity and the percentage of extender present in the ink.

It's always a case of trying to identify which variable is the most problematic with the color before fine tuning in order to achieve an optimal deltaE result. Even though it's sometimes impossible to refer to a visual, you should always try to corroborate an LCH reading to a visual evaluation. This exercise, along with the help of the strength tool, will possibly help to detect a problem in color combination. This will also help prevent metamerism. (Phenomenon in which two surfaces, that look similar under a particular lighting or illuminant, can look different under another type of lighting.)

COLOR TERMINOLOGY (INKS)

STRENGTH: DENSITY OR COLOR SATURATION.
- WEAK OR STRONG

SHADE (HUE): THE PROPENSITY OF A COLOR TO POINT TOWARD ONE SIDE OF THE COLOR SPECTRUM OR THE OTHER.

HERE ARE THE POSSIBLE TERMS:
- YELLOW (MORE OR LESS RED)
- BLUE (YELLOW SIDE (green) OR RED SIDE)
- GREEN (BLUE SIDE OR YELLOW SIDE)
- RED (YELLOW SIDE OR BLUE SIDE)
- VIOLET (BLUE SIDE OR RED SIDE)
- GREY BROWN OR BEIGE (DEPENDS ON THE COLORANTS USED IN THE FORMULA)

DIRTINESS: PRESENCE OF A ''CONTAMINENT'' THAT TARNISHES THE APPEARANCE OF THE COLOR. OFTEN ASSOCIATED WITH THE PRESENCE OF BLACK IN A FORMULA.
- CLEAN OR DIRTY