Take a look at how Andy Evansen gets the silo in this scene to be located in space relative to the trees and the sheep. On the right side of the silo we can see a distinct edge and a strong value difference between two shapes. On the left side there is some ambiguity about which shape is in front. Halfway up some tree branches merge with the silo, making it unclear which is in front. The artist has allowed this sleight uncertainty by making a soft edge where the shapes meet. He seems to have decided that the combination of variables at work on the right side is sufficient to establish the location of the shapes. He knew could afford to lose the edge a little. Why do you think he wanted to do that?
Now let's look at those sheep. They are the same colors and value as the silo, but they stay distinctly separate. What has Evansen done to establish this separation?
Here are a couple more landscapes to ponder:
Very subtle work! A little bit of white goes a long way.
If you mentally peel away the tree branches you can see that the distant hill and the foliage of the tree are not separated at all, and yet there is no confusion about which feature is closer.
Choose one of the following photos and experiment with getting the shapes to separate and combine. If you decide to try making a proper painting, remember to keep it simple!
If you'd prefer to copy one of the paintings, remember that the spirit of the painting is more important than the specific marks. Empathy rather than accuracy.