how to draw portrait sketching

The problem I have is that the artist's paintings are very flat portrait sketching, so how are you supposed to draw a 3D object on a canvas in two dimensions? Here are some concepts that I learned from a book (artist portraits) by portrait sketching combined with my own experience.

Suppose you start your designs with a sketch of the front shading artist portraits.Now start trying to create a solid object from the first sketch is quite difficult portrait sketching. It is difficult to see where one begins and the other ends edge. This is why I break the head of a group of planes is so beneficial.

The right way to learn portrait sketching:

Aircraft on one side are more visible when bright light hits at an angle. These devices are essential to the development of a strong portrait sketching, realistic portrait. It will help you know what values ​​to give different parts of the face.

Tip: If you're not sure of the value to a portion of the head (portrait sketching) remember that the lower part of the head light gets darker portrait sketching. The more light you get the lighter it will be paintings art.

Here is an example of the basic plans of the face. I recommend you memorize the positions of the different levels, and you can benefit in many ways artist portraits. Sometimes, in the preparation of photographs is difficult to know what value to give some part of the face, but if you understand the construction of the head, and the light source portrait sketching, it is easy to identify the value to be applied to this area .

It is not necessary to dissect the head parts each time you draw a face. The goal is to understand the construction of the face artist portraits, and the balance you need between the lines and hard edges, smooth lines and soft curves. The balance between the two will reveal the depth and nature of its design, but it looks like something set in stone paintings art.