The Hue Angle

The Hue Angle tells us what colour the sample is. It is a very quick and easy way of visualising where the colour is.
Hue Angle is measured from the a* axis in an anti-clockwise direction

0 degrees is RED
90 degrees is YELLOW
180 degrees is GREEN
270 degrees is BLUE
and,
360 degrees is back to RED again.

In combination with CHROMA, this gives us an alternative expression for the CIELab values, for identifying the same sample in colour space.

For example:     L =  50                      L = 50
                        a* = 20                      C = 40
                        b* = 30                      h = 55 degrees

These are the CIE Lab and LCh coordinates for the same mid shade orange, shown opposite: