Continuing the evidence analysis in the McPhee case, the next physical evidence my lab partner and I analyzed after the blood evidence was ink. The purpose of this lab was to find color patterns and Rf values of the different types of inks found at the crime scene and on the persons of interest (POI) using a technique called Thin Layer Chromatography (TLC). We then compared the crime scene inks to the POI inks to further eliminate people from the POI list. More specifically, we tested the ink samples from the stamp pad at the entrance, calligraphy ink and security ink for their compositions. We also tested ink samples found on the persons of interest. Two methods that could have been used to analyze ink evidence were Ultraviolet (UV)-visible…show more content… We observed that lane V(Olivia McPhee) had blue, pink and fluorescent orange color components. The lane starts with a blue, thin, straight, fading streak that extends up to one-thirds of the solvent front. We gave it an Rf value of 0.07 because we measured to the middle of the blue streak. There is a light, thin or almost invisible pink streak starting from the endpoint of the blue that got darker and slightly thicker as it rose. This pink streak stops at approximately a quarter of a centimeter before the solvent front and has an Rf value of 0.78. The last pigment in this sample is the flourescent orange, whose extremely thin streak started right after the blue and ended slightly before the pink. We gave this an Rf value of 0.60. The next sample we tested was S2(Katie Wnuk), which had blue, purple and pink color components. This lane starts of with a very thick, dark and short blue streak and extends up to approximately half a centimeter. The blue, with an Rf value of 0.10, fades a little bit, and a thick, slightly slanted purple line starts just about 3 millimeters after. This purple line- with an Rf value of 0.61, goes up to slightly past two-thirds to the solvent front and ends by fading into the pink. The pink portion of the column starts out from the purple and extends up to approximately a quarter centimeter and again ends about a quarter centimeter before the solvent front. We gave the pink streak an Rf value of 0.79. The next sample we tested was S5(Elijah Cordero), which had blue, pink and fluorescent orange color components. The column starts with a straight, thick and dark blue streak that gets thinner and lighter as it rises up to one-thirds of the solvent front. We gave this pigment an Rf value of 0.15. The next pigment, which is fluorescent orange, starts where the blue ended, as a thin, straight
