After the prepared tree-shaped strip were dipped in 6mL
of water for 30 min, different intensities of blue color could be
observed. The different concentrations of BSA solution could be
judged by eyes semiquantitatively or analyzed the pictures taken
by camera or cell phone by Quantity One. In our experimental, camera
and parameters are as follows: Olympus FE-210 digital camera
with CCD sensor (Tokyo, Japan), maximum resolution 3072×2304
pixels, programmed auto exposure without flash light, the object
distance is 30–40 cm. These photos were imported into the computer
and color differences were analyzed by image software
Quantity One (Bio-Rad company). Darkness density of each dot
was picked to describe color difference among the volume data
in Volume Analysis Report.