Colorimetry by a Smartphone.

A smartphone has been used for colorimetry, both by means of the built-in camera and by means of a clip-on dispersive grating. Certified colorimetric samples provided by Labsphere® and several samples of cloth fabrics with a palette of the most common colors were considered as test samples. Color measurements directly performed by means of the smartphone camera alone were obtained using the “RGB Detector” App, downloaded from the Google Play Store. More precise measurements were obtained by means of the commercially-available GoSpectro grating and related App. In both cases, in order to quantify the reliability of smartphone-based color measurements, the CIELab color difference ΔE between the certified and smartphone-measured colors were calculated, and are reported in the paper.