I've always loved colours that granulate - that is, create a varied speckling across the wash which had traditionally been present in certain pigments such as French ultramarine and cobalt blue, for instance. This summer, my attention was drawn to the Daniel Smith watercolours which are imported from America, as so many of the colours in an extraordinarily large range tend to granulate.
In this small section of a watercolour painting you can clearly see the strong granulating effect in the sky area. This colour is Zoisite Genuine, a grey-green that is especially useful for mixing subtle greens by adding one of the yellows to the mixture. It also has a slight tendency to intermittent sparkle when caught in a certain light, and is excellent for those areas you wish to play down, yet retain a little interest in the form of the granulations.
Moonglow is another colour that granulates well, a deep violet that would be ideal if you need a 'mysterious dark' with a little warmth. Whilst it may be an exciting addition to your halloween paintings, it could inject some lovely moody atmosphere into your landscapes, and I look forward to experimenting further with it.
Another exciting colour is Quinacridone Deep Gold which can impart a glorious rich glow to your skies, autumn scenes, or many other applications in a painting, and if you want intensely blue summer skies the Daniel Smith Manganese Blue is a knock-out. I should also point out to those who like Yellow Ochre, but not its opacity, that in this range the pigment is transparent!
I've only tried a few of the colours in this range, but from what I've seen they do give exciting possibilities. As artists we should always be on the look-out for new colours to try out. You can buy test sheets of the whole range and these contain a small blob of colour of each pigment that you can try out. Many of the colours are metallic, they shimmer and sparkle, so not all are suitable for traditional watercolour painting, but if you wish to look further see http://www.premiumartbrands.com