This morning I decided to do a few things I haven’t been too fond of in the past. One is negative painting. The other is using glazes. That’s what I did here. The first layer was a warm yellowish wash, very thin. From there, about 3 or 4 consecutive layers of blues and violets around the main trunks, and then over the ones to the sides, making them bluish. I then used a rigger brush (for the first time) to create branches.
Overall, the picture works, but the areas I can say shouldn’t have happened are the branches in front of the central trunk. The other thing I need to do is to create better contrast on the branches, in particular it seems on the right. I would like to see more blue in there, in narrow strips using a flat brush. I may do that later.
The idea behind this painting a sycamore tree in moonlight, with the above exercises to accomplish it. I thought ahead more than I usually do, considering colors and such, as well as the approach to creating what I desired as an end product.
Ink, Yarn & Beer 
ooo and ahhhh, love this image.
The lightest patches on the edges of the branches and trunks work really well against the dark background of the sky as does placing the dark branches at the bottom, thus pushing the tree back.
Thanks, Graham. I think I may do this painting again, with some variations. It’s something worth repeating as far as a study goes. Practice, practice, practice!