Whether it's the fashion or the foliage, there's something about choosing a nail polish in the autumn that makes us think more critically about undertones. If you're at the salon, that might translate into spinning an almost-black bottle of lacquer under the light to detect the flecks of burgundy that will make it feel like a semi-precious stone on your fingernails. But, where the lighter colours are concerned, those nuances can feel less autumnal. That is, unless you land on the perfect olive green.