Portrait Comparisons: Rosalba and Maurice
These are not portraits of Rosalba Carriera and Maurice Quentin de La Tour, but they are portraits by Rosalba and Maurice. The difference in time of the rendering was only about 30 years and if you look at portraits painted in the second half of the 18th century, there is a marked improvement in what we call as realism.
Now no one can deny that there is a realism of Maurice's portrait of the great mathematician, Jean Le Rond d'Alambert that the portrait of the unknown lady by Rosalba doesn't have. And understanding the difference in the two portraits - which admittedly both are quite good - helps explain the basics of portraiture.
Believe it or not, most people's faces have a lot in common. In particular the line of the eyes for adults should be set about halfway between the top of the head and the chin. There are virtually no exceptions to this rule unless there is a particularly unusual tilt to the head or the subject has some congenital condition such as acromegaly (which lengthens the jaw). Of course, if the subject sports a particularly towering hairstyle you take that into account but usually the extra height of hair has little effect on this rule.
Ironically, the usual mistake of the beginning portraitist is to make the eyes too high. That's because the tendency is to ignore the hair and see the top of the head as the top of the forehead. The real top of the head is further back between ½ and ⅔ of the way back from the forehead. It is this top that is the real head height for locating the eyes.
On the other hand, we see that Rosalba's portrait - used for her work The Allegory of Art - has the eyes actually a bit low. Now you may think this is because her head is tilted a bit down. Actually with of the contours of the head being what they are, moderate tilts make little difference in the line of the eyes. If the chin lowers a bit the top of the head will actually raise up a corresponding amount or at least doesn't drop. So any change needed from the halfway rule is slight for most orientations of the head.
Maurice's portrait, though, maintains the half-way rule with only a slight margin needed for the wig. So we have a much greater sense of realism.
Also note how in Rosalba's picture the eyes are particularly wide. This isn't simply an illusion because they are partly closed. Instead, the actual width is outside the normal range. A lot of pictures from the early 18th century - and some later - tend to have the larger eyes and often with hooded eyelids. This tends to give the subject a sultry look that some of art patrons evidently liked. You'll see this style sometimes even into the 19the century.
Maurice, though, painted Jean's eyes more in scale. They are smaller than Rosalba's and clearly not as wide. Again, we get a more realistic picture.
Finally, note the wide sunny smile of Jean and compare this to the small coquettishly curved lips of Rosalba's portrait. Once more Maurice kept within the range of reality while Rosalba had the mouth of her subject compressed too much.
In short, realistic portraits - even if they have unusual color choices, impressionistic techniques, or modernistic methods - pay close attention to the proper proportions of the face and head anatomy. The first two rules in portrait drawing or painting is to 1) establish the height and width of the head and 2) draw in the line of the eyes at halfway between the top of the head and the chin. The the shadow under the bottom of the nose about 1/2 of the distance from chin to eyes and the mouth a little above the shadow. Then you can then start adding the details and making adjustments as needed. But if something looks a bit off, always check your proportions.