Darker, Duller and Cooler
Bird Holes (sometime known as sky holes) are very important in painting trees. When painted properly, they give a landscape that realistic airy three dimensional look. Here are some pointers on how to paint them properly.
DDC = Darker, Duller and Cooler. The first thing you need to know is you can’t put the same sky colour inside your trees. The problem is that those little "holes", being smaller than the sky, create an optical illusion. When painted the same as the sky they look like they “pop”. They appear brighter. As you may already know lights expand and darks contract, so those areas appear lighter than they really are. To compensate for this, one needs to paint the sky holes a little bit darker, a little bit duller and a little bit cooler than the sky itself. By doing this, the holes will appear to recede behind the trees and create an illusion of distance.
Knowing what colour to use is only half the battle. Knowing where to put them is the other half. If we look at how trees grows this will give us a good indication of where we should put sky holes. The tree starts as a stick and then has branches that grow from it into a certain size of a bouffant. Once this section fills out a new section begins to grow and you will see new branches start to grow out from this bouffant. Thus a new bouffant section is born. Once this section is done, another bouffant grows. In between the bouffanty sections is the key. This is where you place your sky holes. Between first growth and second growth sections there is a small amount of empty space. This allows for placement of sky holes. Try to keep them next to the branches and don’t forget the DDC rule. BAM you have proper sky holes.
Note: You can also use this same colour on the edges of the tree for shaping the tree.
Your friend in art Doug