2.3. RGB capturing system and procedure
A custom-built color detection box (Fig. 1) was used to
eliminate any effects from environmental light. The box
(8.0 cm 11.0 cm 5.5 cm) was made of opaque black corrugated
plastic board with an internal white background. A flat cap PCR
micro-tube was hung at the top of the box as a reaction container. A
5 W cool daylight Philips light bulb was put at the top of the box as
the upper light source, 2 cm from the micro-tube (this was found to
be the optimal distance). The intensity of the color product inside
the micro-tube was detected using the ColorAssist app (FTLapps,
Inc.) for an iPhone 4.0 in the flash-off mode.