hemoglobin molecules have different colors right so we can quantify the concentrations of both forms from which we can compute their oxygen saturation of hemoglobin right this is a very important parameter and we can detect arteries and veins by looking at the colors and this is actually coming out of our finger cuticle so we can image a human capillary loops and watch the color of the blood vessels and that tells you where oxygen is released the most it turned out at the tip of the capillary loop seems to release most of