with the colour that runs underneath your skin. so you can be very light and be pink, or you could be very light and be yellow and it's very important to know that so you can actually get beauty products that work for you. there are different ways to measure skin undertone, but the skin colour chart here which powers the tool makes the method unique. having an olive complexion i really struggle to find make up that will match, and being a biochemist, i decided to look into it and i discovered that beauty magazines were recommending, look at your veins and that will help determine your undertones. we realised there was no way that actually skin was being classified accurately, so we thought we need to start right at the beginning, we started by reclassifying the entire human skin gamut and came up with this index and that gave us the base to say now we understand the classification of human skin, we can digitalise the system.