The text discusses the method of dividing the human head into sections and drawing operational lines for an accurate artistic representation. These guidelines vary depending on the head’s angle, such as when tilted to the side, affecting how features like the nose, mouth, and eyes appear. It also explains the use of tools like a pencil holder for drawing curved lines and discusses the importance of foreshortening in creating realistic perspectives.
We set the scale AB (see Plate 13, fig. 1) equal to the height of the head; then we divide this scale and the head into four equal parts, as we did for other heads. Through these division points, we draw operational lines that differ greatly from those of other profiles: because here, the head is tilted to the right, these lines describe circles, which we see from below, rather than straight lines as in the profiles of Plates 11 and 12. It is understood that the more the head tilts, the more the lines will appear curved. To ensure the curvature of these lines, one can use the means indicated on Plate 4, fig. 8 and 9. It is true that these operational lines are imaginary, but on a plaster model, they can be marked in the following way. A black thread is placed over the nose attachment, through the upper eyelids, then over the ear, and attached behind the head. A second line is passed under the nose, under the ears, and also attached behind the head, and a third passes through the mouth opening: it is observed that these threads must be parallel to each other. Then, to find the curvature of the line, we use the method indicated on Plate 4, fig. 8 and 9.
Another method can also be used. The pencil holder is held horizontally, level with the bottom of the ear. In this way, it is easy to see if the bottom of the ear, in this position, appears to reach the middle or the tip of the nose. The point marked here as P is found again by lowering with the pencil holder. Having thus the points represented by P and by D, then the point given by the scale, it is easy to draw a curved line through these three points. We mentioned dividing this head into four equal parts like the heads in Plates 11 and 12. The only difference is that it is quite evident that in this position, point C, represented here, is closer to the observer than point E. Thus, the distance from point C to point G presents a plane receding in perspective; and the various spaces found in this plan are seen in perspective or foreshortening. Yet, in nature, these distances CD, DE, EF, FG are equal among them, whereas in this position, fig. 1, these spaces appear to diminish as they move away. Thus, the space represented by DE seems smaller than CD, EF is smaller than DE, and the last segment FG is even smaller than the others. In fact, the top of the head, being almost flat, disappears at once. Therefore, only the fourth part, the space represented by FG, is seen. In this position, very little of the top of the head is seen, but the underside of the chin is visible. One would not see this if the head was upright, and in linking the line or contour represented by LM, only line NC would be visible. With the head tilted, the features appear broader and the length of the nose is always equal to one-quarter the height of the head, or one part; but in this position, the underside of the nose and the sides of the operational line FG appear somewhat foreshortened. In this position, the mouth appears closer to the nose because the space from the mouth opening to the nose is seen in foreshortening. The ear always appears the same width but appears more curved, and the eye looks more closed. Here, we do not discuss the various changes the features undergo, intending to discuss them further in relation to the organs in general, focusing only now on their positions and proportions.
If the same profile, always looking to our left, is tilted towards us, that is, to its left, the operational lines become curved in the opposite direction of the lines in fig. t. In this new position, it is evident that point H, fig. 2, is closer to the observer than point C. But, the space represented by ED appears larger than JC; space EF appears larger than ED, and space HF much larger than FE, as we see a part of the other half of the top of the head; this half is represented here by space HK. GHJ represents the operational line, dividing the head into two equal parts. Regarding the features, they are the same as in figure t. The widths are always the same, but the lengths are foreshortened.
Translation Notes:
Operational lines: These refer to imaginary guidelines that artists use to measure proportions and positions when drawing the human head.
Foreshortening: This is a technique used in perspective to represent an object or figure in a picture in depth.
Pencil holder: A tool used to hold drawing instruments in place for steady and accurate placement of lines.