L*a*b* vs. L*C*h Coordinates

Human perception of color varies greatly from person to person. Things like color blindness, eye fatigue and different light sources all affect the way each individual sees color. To help eliminate variation and standardize color measurement for consistency, the L*a*b* and L*C*h* coordinates were developed.

What Does L*a*b* Stand For?

L*a*b* is a model for plotting absolute color coordinates and for comparing the coordinates of two colors to assess their specific differences.

L*a*b* stands for:

  • L*: Lightness
  • a*: Red/green coordinate
  • b*: Blue/yellow coordinate

How Does L*a*b* Work?

When you look at a L*a*b* chart, you’ll see that the a* axis runs from left to right. A color measurement that falls on the positive side of the red axis marks a shift toward red, while a negative measurement indicates a shift toward green.

The b* axis runs up and down, with positive b* axis measurements indicating a yellow shift and negative measurements indicating a blue shift.

The L* axis is in the center. A zero value on the L* axis represents total light absorption or black, with coordinates in the middle of the axis representing gray or neutral.

What Does L*C*h Stand For?

The L*C*h model is also used to communicate the color of an object and to simply and precisely demonstrate how it is different from another color based on their coordinates. L*C*h has the same color space as L*a*b*, but it uses cylindrical coordinates instead of rectangular ones.

L*C*h stands for:

  • L*: Lightness
  • C*: Chroma
  • h: Hue angle

How Does L*C*h Work?

On an L*C*h diagram, the chroma (C*) axis starts in the center at zero. Chroma indicates how bright or dull a color is, and a color’s chroma value is measured as the distance from the lightness (L*) axis. The hue angle (h) starts at the positive side of the a* axis and is denoted by degrees. On this scale, zero degrees equates to red, and 90 degrees equates to yellow.

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Because the human eye cannot detect differences in chroma, hue or lightness equally, the L*C*h coordinates are especially important to understanding a color’s complete fingerprint.

L*C*h and L*a*b* Color Generators From HunterLab

For precise L*C*h and L*a*b* calculations, HunterLab offers a line of spectrophotometers that are designed to provide simple, accurate color measurements. Spectrophotometers remove human subjectivity and challenges in color perception to ensure control and correctness in production. When you use a spectrophotometer, you can trust that your products are manufactured with reliable color harmony.

Whether you need the color of vinyl siding, textiles or automotive parts to match perfectly, our spectrophotometers provide flexible and consistent measurements to help you achieve your color goals. For more than 65 years, our products have been used by workers in a wide range of fields to define, communicate and standardize their colors with efficiency and exactness.

Browse our different models to get a sense of what we offer, and contact us to find out more about how our spectrophotometers can enhance the color accuracy of your products.

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