“…18 Abrazheev et al 19 determined arsenic by a modification of the Gutzeit method in which a function analogous to absorbance was calculated. The first report of the use of the separated red, green, and blue (RGB) colour intensities was in 2002 by Kompany-Zareh et al, 20 who derived a similar absorbance function. Paciornik et al 21 compared the performance of the RGB; cyan, magenta, yellow (CMY); and hue, lightness, saturation (HLS) colour space models and concluded that the best parameter to use was the hue, H. More recently, Sharma et al 22 analyzed the images produced by reaction of arsenic with sulfanilic acid and N-(1-naphthyl)ethylene diamine dihydrochloride solution.…”