Above is a picture taken from tree, which leafs are turned from green to yellow. The spectrum measured from a yellow leaf can be seen below.

Color coordinates calculated from the spectrum
Spectrum Yellow
x 0.4808
y 0.4374
z 0.0819
X 46.5002
Y 42.3015
Z 7.9185
R 68.3249
G 37.0805
B 7.6240
L* 71.0783
a* 18.7915
b* 66.6090
u' 0.2639
v' 0.5402
u* 61.1995
v* 66.2518

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