  Leaf colors of a plant can be used to identify stress level due to its
adaptation to environmental change. For most leaves green-related colors are
sourced from chlorophyll a and b. Chlorophyll concentration is normally
measured using a spectrophotometer in laboratory. In some remote observation
places, it is impossible to collect the leaves, preserve them, and bring them
to laboratory to measure their chlorophyll content. Based on this need,
measurement of chlorophyll content is observed through its color. Using CIE
chromaticity diagram leaf color information in RGB is transformed into
wavelength (in nm). Paddy seed with variety name IR-64 is used in observation
during its vegetation stage t (age of 0-10 days). Light exposure time {\tau} is
chosen as environmental change, which normally should be about 12 hours/day, is
varied (0-12 hours/day). Each day sample from different exposure time is taken,
its color is recorded using HP Deskjet 1050 scanner with 1200 dpi, and its
chlorophyll content is obtained from absorption spectrum measured using
Campspec M501 Single Beam UV/Vis Spectrophotometer after it is rinsed in 85 %
acetone solution and the information from the spectrum is calculated using
Arnon method. It has been observed that average wavelength of leaf color
{\lambda}avg is decreased from 570.55 nm to 566.01 nm as is measured for t = 1
- 10 days with {\tau} = 9 hours/day, but chlorophyll concentration C is
increased from 0.015 g/l to 3.250 g/l and from 0.000 g/l to 0.774 g/l for
chlorophyll a and b, respectively. Other value of {\tau} gives similar results.
Based on these results an empirical relation between concentration of
chlorophyll a Cc-a and its wavelength {\lambda}avg can be formulated.
