Ute asked me recently: “I got stuck on greens before, where I could not achieve values and as you said, you can’t add more colour to get value. How do I avoid the same mistake when mixing greens? I basically used blues and yellows. What other options are there?”
Modifying any full-blown colour is a bit of a trade off. I too use yellow and blue for my greens and if I used a green out of a tube, I’d have the same problem, essentially because green is green. Every full colour has a natural value and to darken you have two possible paths. You could add a little of the complement. This is taking colour out (the complement being the opposite colour) and so the mix is darkened and consequently, dulled: because there is now less of the original colour left – some now being neutralized by the complement. Adding black, which I don’t do for a variety of reasons, is effectively doing the same thing, black containing the complement.
The alternative is to use a colour that is closer on the colour wheel, preferably one that is naturally darker. This has some darkening effect, however more colour is retained, howbeit shifted towards the mixing colour. In this way, I prefer to “blue” my greens, adding a nice dark ultramarine, which retains some greeniness, whilst adding value quickly. In doing so, I am following the lead of the impressionists – cooling rather than dulling colour.
Break-a-Brush!
David