L* D65/10° (%) SCAN P72
L* C/2 (%) ISO 5361

L* is a measure of perceived lightness. The scale of L* is 0–100.
L* is measured with an instrument that emits D65 light, i.e. a light that is related to daylight with the same amount UV light as in a winter day. 10° is the viewing angle.

If the Y value is over 60 %, the L* is fully possible to be exchanged with the Y value, because they correlate near to 100 %.

a* D65/10°
a* C/2

%
a* is a measure of the hue on the red/green axis. A positive value of a* means red and a negative value means green.

a* is measured with an instrument that emits D65 light, i.e. a light that is related to daylight with the same amount UV light as in a winter day. 10° is the viewing angle.

b* D65/10°
b* C/2

%
b* is equivalent with measure of hue on the yellow/blue axis. A positive b* means a yellow hue and a negative value means a blue hue.

b* is measured with an instrument that emits D65 light, i.e. a light that is related to daylight with the same amount UV light as in a winter day. 10° is the viewing angle.