The arm that grew
Meera is drawing a 25-minute seated pose in which the model's right arm points almost directly toward her, holding a small bowl. The model is 1.70 m tall and the drawing is 19 cm from crown to heel. Meera's head unit is 2.8 cm; she has drawn the foreshortened right arm as 11 cm from shoulder to wrist because she knows the arm is long. The torso looks compressed, the wrist is drawn as a full ellipse, and the hand sits outside the bowl. With 18 minutes left, she has blocked the main masses but has not started shading. The exam asks for proportion, gesture and structure, not a finished portrait.
1. Using the head as unit, test whether Meera's drawn arm is credible. Show the arithmetic and explain what the foreshortening should do to the arm's apparent length.
Read the worked answer
Head unit = 2.8 cm. Drawn figure height = 19 cm, so the figure is 19 / 2.8 = 6.8 heads tall. That is short for a standing adult but can be plausible for a seated pose depending on where the heel is; the more serious error is the arm.
The drawn arm is 11 / 2.8 = 3.9 heads from shoulder to wrist. In a standing adult, shoulder-to-wrist is roughly 3 head lengths; in a seated pose it does not become longer. A limb pointing toward the viewer is foreshortened, so its projected length must be shorter than its actual length, not longer. If the actual shoulder-to-wrist is about 3 heads, the projected length here should be roughly 2 to 2.6 heads, or about 5.6 to 7.3 cm, depending on the angle.
An 11 cm arm is therefore impossible in this pose. Meera has drawn the arm she knows is there rather than the arm she can see. The compressed torso is a related error: she has kept the arm long and squeezed the body to fit the page. The full figure should be checked against 7 to 7.5 heads if standing, or against the seated proportion from crown to seat, and the arm must be measured as a projected shape.
2. Explain the difference between actual arm length and projected length, and give two sighting methods Meera can use in the remaining time to catch the error.
Read the worked answer
Actual length is a property of the model's body and does not change. Projected length is what the arm subtends on the picture plane. When the arm points toward the viewer, its depth component increases and its projected length decreases; the wrist also overlaps the upper arm, and the hand becomes larger relative to the forearm. Meera is treating projected length as if it were actual length.
Sighting method 1: pencil comparison at arm's length. Hold the pencil at a fixed distance from the eye, mark the apparent shoulder-to-wrist length on the pencil with the thumb, then compare that mark with the apparent head height. If the arm appears about two head lengths, it must be drawn at two head units on the paper. Repeat for the upper arm and forearm separately, because the elbow may be the most foreshortened point.
Sighting method 2: negative space and overlap. Look at the shape of the cloth or background between the arm and the torso. If the arm were 11 cm long, that negative shape would be much narrower than it appears. Also check the overlap: the wrist should sit in front of the elbow, and the hand should overlap the bowl rim. Drawing the full ellipse of the wrist is another symptom of drawing the known form rather than the seen shape; a foreshortened wrist is a narrow ellipse or a nearly straight contour.
3. Plan the remaining 25 minutes of the pose. State what Meera should do in the first 2, next 5, next 10 and final 3 minutes, and what she should sacrifice if time runs out.
Read the worked answer
First 2 minutes: restate the gesture line from the crown through the spine to the supporting seat, and mark the shoulder-to-wrist axis as a single tapering wedge. Do not draw fingers or facial features.
Next 5 minutes: block the head, ribcage, pelvis and the foreshortened arm as simple masses. Check the head unit against the torso and the apparent arm length with the pencil. Move the hand to the bowl rim before any detail is added. This is the stage to correct the 11 cm error, not later.
Next 10 minutes: establish structure and the main shadow shapes. Draw the overlapping contours at the shoulder, elbow and wrist; keep the wrist ellipse narrow; indicate the bowl as an ellipse in perspective. Put in the core shadow and cast shadow, but keep them as flat shapes rather than blended finish.
Final 3 minutes: step back and check proportion, the gesture, and the darkest darks. If time runs out, sacrifice fingers, facial features, hair texture and clothing folds. Keep the gesture, the head-to-body ratio, the foreshortened arm and the overlap with the bowl. The exam asks for proportion, gesture and structure, so a resolved structural drawing with unfinished shading scores better than a detailed hand on a wrong arm.