Accurately mixing an ink to a specific pantone colour is certainly an art. In this case we are mixing pantone 375 a green. As you can see blue and yellow weighed to the correct proportions should hit the colour correctly, but at Park Lane we also add other colours or additives to make it print better or improve the match to the pantone book. In this case we have added opaque white which produces a better lay down of solid ink. For 25 years we have been mixing inks and have a huge database of formulas, its the extra touches that make the difference, a bit like baking!