Green beige walls, butterscotch sisal carpet (source)
The first semester I taught Colour Theory, I was well into a long talk about colour and specifically the many undertones of colour. All was going well (or so I thought) until one brave soul at the back of the class tentatively raised her hand. “What’s an undertone?” she asked. I was dumbstruck. In that moment, I couldn’t even explain it (or not very well) because it’s so obvious to me but only because I’ve been doing this for so long.
So the next semester I was prepared with a definition and an explanation. And here it is:
Undertone: A colour applied under or seen through another colour.
Clients are always asking me “What’s the difference between this colour and that one, which one is warmer which one is cooler, etc?.”
As soon as I say, “This one’s more orange, or that one is more blue”, they mostly see it immediately but it takes a trained eye to be able to wade through all the possibilities and especially the undertones of beige, (which are the most confusing) to pick the one that’s right for you.
It’s much easier to see it with stronger colours like these:
In the living room above, the sofa has an green undertone and the purple area rug, a red undertone.
While this might seem obvious to you now that I’ve described them, the undertones of these colours will change again as soon as a warmer or cooler colour is placed next to them. If I hung this piece of art (below) into the bedroom above, suddenly the drapes in the room would appear greener/cooler while the new piece of art is much more orange/warmer.
Basically what it comes down to is that ‘technically’ you can’t actually call a colour ‘cool or warm’ unless you are comparing it to another colour. You might have a personal reaction and opinion on whether the blue in the bedroom above is cold, but until its compared to a periwinkle blue (warmer) or a greener blue (cooler) it’s not cold or warm.