Thanks Colin.

The flowers are mostly done in gouache, very diluted in case to flow like watercolour. The leaves are also gouache. But the “trick” is to take a little ink and add it to the mixture in places (particularly the leaves) and then one gets the subdued effect you mentioned, and a little separation between gouache and ink to add to the texture. The ink is used in its pure form in places, and then allowed to bleed into the gouache, and the ink is also used to darken colours. It sounds controlled, but the reality is there is the same surprise element one has with pure watercolour – you never know what the water will do. (This is a very Daoist thing).

An extension of this is Japanese Sumi-e where pure ink is used.

Give it a try – it is enormously relaxing – a bit like meditation.