Okay, here is a tutorial lesson thing I gave my highschool art club. It is on the basics of portraiture, and while it is a huge and complex topic, I mainly want to get across one point—DON’T FOCUS ON DETAILS OF THE FEATURES, RATHER TREAT THE HEAD AS A WHOLE AND USE VALUE TO REPRESENT IT. Perhaps a bit wordy and not too clear. But anyway, I’ll explain in detail what I mean.
Before I get to that however, I would like to quickly gloss over the basic proportions of the head which I consider to be of the most importance. These are not meant to be followed exactly, and not everyone will fit in perfectly with these. In fact it is the minor variations in these proportions that give someone their own likeness that is different from everyone else’s. Despite this, they do come in very handy to know as it will allow you to understand the placement of things and to see them quicker and more accurately.
In the picture below I have taken a painting by Sargent, and overlaid a few lines. In red, there is the angle of the head noted (a line running through the center of the face). As you can see, it is tilted slightly, which is very important to know when drawing the rest of the head accurately. This line is subdivided into three equal parts; at each third there is a line that runs at a 90 degree angle to the tilt of the head. The topmost third is the forehead—it begins at the hairline and extends to the brow ridge (the bony area above your eyes whereupon the eyebrows lie). Note that out of the thirds mentioned here, this one will vary more than the other two due to the fact that hairlines have a nasty tendency to recede as one ages. The next third runs from the brow ridge to the bottom of the nose, and the last third is from the bottom of the nose to the bottom of the chin.
While the previous proportions dealt solely with the face, this next one deals with the whole head. It is very simple: the eyes lie at the halfway point between the top and bottom of the head. It is important to remember though that they lie at the halfway point of the SKULL, so with hair they may appear to be even lower on the head. It is a common mistake for beginners to put the eyes too far up on the head.
The last set of lines (blue) are very important. They mark the distance between the eyes, and the distance from the tear duct to the bottom of the nose. Typically, the distance between the eyes is equal to one eye length, and the tear duct lines up with the outside of the nose. The length of these lines vary from face to face, but are extremely important to get right, as they are perhaps the most crucial factor in getting the sitter’s likeness in the portrait.
In the next image I am using another Sargent portrait. Most beginners begin drawing a portrait by drawing the eyes, then the nose, then the mouth. Usually they will try to get all the nice little details in the eyes—the eyelashes, the tear duct, the complexities of the iris, the bits of reflected light. THIS IS THE WRONG APPROACH. It results in a very flat looking portrait and will not hold together. Instead, IGNORE THE FEATURES OF THE FACE. I cannot stress this enough. Look for the basic patterns of light and shadow. You should be able to separate the two into distinct sections. Everything in the darks is darker than anything in the lights. If you look below, I have edited the portrait so that it is only in two values. Despite the features of the face not having any detail whatsoever, it is still very recognizably a face. Only once the basic lights and darks have been established can you go and put in the features.
The next picture contrasts the two methods. Both have the features placed properly in the head using the proportions outlined at the beginning. But notice the difference. The one on the left doesn’t need any details at all, and still looks fine. The one of the right by comparison is very flat. I have also intentionally drawn several common mistakes in it. Only worry about these once you have a good head without features first. The eyes have lots of eyelashes—you don’t ever need to draw eyelashes, at most put a slightly darker shadowy area around the eyelid hinting at eyelashes. The iris is completely revealed which gives the person a look of surprise. The bottom of the iris should be level with the bottom eyelid, and the top third or so of the iris should be covered by the top eyelid. The bridge of the nose is drawn in. Don’t do this. Reveal it through value, not a big dark line. The lips are outlined. Again, use value to represent them.
The head on the left shows the common areas that shadows appear. It holds true for most normal lighting conditions (there are some exceptions such as light coming from below, but these are unusual). The general areas are as follows: an area around the eyes caused by the cast shadow from the brow ridge, the area under the nose, the top lip, and an area on the chin right below the bottom lip. Also, since the light source is slightly to the side and the head is a 3d object in space, the side plane of the head and nose are also dark.
But in order to understand how to properly place everything, a thorough understanding of the head is required. To have this one must study the skull, as a head is just that with a thin layer of muscle and fat on top. Below shows how understanding the skull helps with drawing the head. If you are serious about portraiture it would be wise to either invest in a plastic skull (beware that many are inaccurate, so get a good one) or at least copy many drawings and photos of skulls until you understand its form very well.
I would last like to leave you with a series of progress shots from a painting by Harold Speed, in which you can see everything I have just explained. At the beginning stages he begins by blocking in the basic lights and darks in the same manner as I outlined above (features such as eyes and mouth aren’t even put in). The dark areas are around the eyes, beneath the nose, side plane of head, and beneath bottom lip. Note also how much it resembles a skull at this point. He clearly is very aware of the structure of the head. It is only as he progresses that he adds the features and details.