– use a draw to study the human face: it is the easiest because you can understand better how the construction of the portrait is made, how to put shadows and accents.
– use a photo of a human face: it’s like having a draw already. The photo is flat 2D and you won’t have the problems in knowing how to express the tridimensionality
– use a sculpture like below: the stone, the marble or the wood have very good defined surfaces because of their materiality
– draw after a real human portrait: the last step, the most difficult because you will have to understand the anatomy, to understand the plans of the face in order to shade them correctly, to see how to express the skin materiality (carnation), how to put accents, how to make your draw look like the model
– I added a computer rendered portrait to understand the stages of drawings: from the construction lines, through the construction plans, up to the shading and materiality.
These should be the stages of any drawing. We have to analyze the plans, to understand them, and then we will see that it is easy to draw even without having the model in front of our eyes.
Once we understand the principles of drawing, everything will be easier. Even to draw things that we imagine. If we know the plans and the construction, we will know also how to shade them correctly.
P.S: The rendering is an image that I saved long time ago in my computer, and I cannot find the credits anymore. Please write me and I will post it asap. Thank you.