mDSLR camera image
analysis in universal pH indicator paper disk using various colour space models
for quantitative approach
Daruwala Kainaz Dhanjisha and Baskaran Kamesh Viswanathan
Res. J. Chem. Environ.; Vol. 30(1); 11-19;
doi: https://doi.org/10.25303/301rjce011019; (2026)
Abstract
Universal pH indicator paper is frequently used to measure acids and alkaline in
solutions. A digital single lens reflective camera captures the colour changes of
the universal indicator, allowing for the determination of unknown pH values based
on a colour chart. This study involved taking images of a 2 μL paper disk. Various
colour models, including RGB, XYZ, Lab, Luv, LCH, CMY and HSL were analysed in the
images. Among these, the Luv model was proven to be 96% to 98% of standard linearity
in acidic and alkaline ranges respectively. The pH was effectively measureable from
4 to 12 with a resolution of 0.5.
The closeness of accuracy and precision shows 96.5% and 99.1% respectively nearer
to a traditional pH meter measurement. In the present study, green and white analytical
chemistry approaches were observed to be 99% and 92.6% effective for the 2 μL paper
disk approach.
