Here's a quick review on the definition of silhouette value, and how it relates to posing characters:
Just as silhouette value is helpful in drawing poses that express what you're trying to say with your characters in a clear way, silhouette value can be helpful in making sure the audience knows what your layout is trying to say and reading it the way you intend for it to be read.
For example, here is a quick drawing of a house and some trees.
You might be thinking that this is a subtle distinction...that the trees are obscuring the house and that's why you can't really read the house. But I think it's more than that. After all, it is possible to have trees in front of the house and preserve the readability of the house, as long as you do it in the right way....more on that in a second.
So in this next drawing, I've moved the trees to behind the house. Now you can clearly see the house shape....but now, the tree trunks aren't silhouetted well. They're right up against the edges of the house. They're cut off and they're a bit hard to read as trees. They're cluttering the edges of the house and now the readability of both the house and the trees is suffering.
Here's another version that works fine too. Here, there's a tree in the front yard that obscures part of the house, but it doesn't really hurt the readability of the house. Why is that? Why is it okay to obscure the corners and silhouette in some cases, and not in others?
This concept applies to big objects in your layout, as well as small ones. When you're drawing objects and props in your backgrounds, keep in mind that most objects have a distinctive silhouette that helps them "read" quickly to the viewer. If you don't stage them in the right way, you can create a lot of confusion in the viewer. Here are some common everyday objects staged from two angles: a confusing one, and one that exploits the silhouette of the object so it can be read clearly.
Silhouette value can be applied in more ways than just in the poses you choose for your characters, and can be very helpful for drawing successful backgrounds as well as successful character poses.