I have just returned from tutoring on a painting holiday in the beautiful Cotswolds in the UK. The area is full of quaint old villages, the ancient houses constructed from a golden limestone and bordered by village ponds, trees, and lots of Wisteria in full and fragrant bloom. It was a fantastic time of painting and making new friends.
I sketched quite a bit on the various day trips out and about, and on my return I have begun to make small coloured paintings in a sketchbook from some of these pencil drawings. Let me show you two of them and then explain why they look different. They are both similar scenes from different places, and I used the same watercolour paints in both. But the top one has significant granulation and the bottom one has not.
What is granulation? Well, it’s an effect which is caused by some paints, but not all. These paints are less finely ground and have some particles of pigment that are larger and which separate out of the paint and settle into the dimples in the watercolour paper, causing a mottled effect as the paint dries. I have recently started using a Daniel Smith colour called Green Apatite Genuine which is great at doing this. it is a lovely foliage green and when it granulates it becomes mottled with brown. This gives a semi-realistic foliage effect without having to do to much.
I also used an ultramarine blue for the skies in both pictures, and the top one has granulated while the bottom one has not.
So, what is the secret? How can you either make granulation happen, or avoid it, even when using exactly the same paints?
The answer in this case seems to have been the tilt of the paper. I painted the first sketch with the paper flat on the table top. This allowed the granules of pigment to settle down nicely into the hollows in the paper (a Moleskine watercolour sketchbook).
The second sketch was painted with the sketchbook on a slope of about 30 degrees. This resulted in a much smoother and flatter finish and little granulation.
I found this to be an interesting way to control the end result, (and anything that helps us control the temperamental watercolour is a blessing!), and I hope it will help you have a little more control over your painting as well.