Coordination in Portrait Drawing:
a case study
Tchalenko, Camberwell College of Arts, Peckham
Road, London SE5 8UF, UK
investigated with the help of an eyetracker, movement
sensor and close-up video filming a well-known painter,
Humphrey Ocean, drawing portraits (Miall
& Tchalenko, 2001). In the present study
we report on a further study of this data concentrating
on the painterís eye-hand coordination. We observed
that, in general, his eye closely followed the drawing
hand, with fixations on, or very near, the line being
drawn. But there were also frequent exceptions
to this behaviour when the artistís eye departed from
the drawing hand to fixate other parts of the drawing
or turned to the model. Examples are presented
for each of these cases, illustrating the process
of visual memory fading and refreshing, and the possible
action of a motor memory component in the drawing
method of this painter.
Ocean is an artist of international repute with work
in major UK and world collections. His portraits
are drawn or painted from life and are realistic,
and his pen or pencil drawings are made with lines
only and no toning. An overriding concern with
him is precision, of which he says: "I
think detail is precision. Detail means where
the line lands, and if it lands a millimetre to the
right, or a millimetre to the left, it changes the
weight, in some way, of the shape that it is describing.
So when that line lands, you just want it to
land in the right positionÖ" On constantly
glancing back at the model he remarks: "There
is a point where the image starts breaking up.
If I draw your eye, I know there is a point where
I start making up or assuming something Ė and then
itís beginning to kind of shatter. So you have
to look back and see what the next bit is." These
considerations, as well as a long working experience
between us, made Humphrey the ideal candidate for
our observations on eye-hand coordination.
When drawing a portrait, Humphrey Ocean, as nearly
all painters who work from life, transcribes, detail
by detail, a visual perception of the model onto the
paper. Consequently, during the making of the
picture, the painterís gaze goes from model to paper
and back again many hundreds or thousands of times.
In the periods when the painter is looking at the
paper and drawing, he, or she, proceeds from a visual
memory of the detail just perceived on the model.
After a short time, usually one or a few seconds,
the painter looks back at the model to refresh this
memory of the detail being drawn, or look at the next
detail to be drawn, and then returns to the paper,
and so forth as the cycle is repeated.
For both portraits examined here, Portrait of Nick
and Luke 2, the artist entered a regular gaze
rhythm from the outset and maintained it throughout
the session with only minor local variations.
While drawing, he referred back to the model about
12 times/minute, usually with single fixations lasting
about 1s (Figure 1). These
rates and durations were also recorded for other portraits
and seem to characterise Humphrey Oceanís way of working,
with the exception of quick (1 or 2 minute) drawings
(Miall & Tchalenko, 2001).
1: Portrait of Nick: The first two minutes
as recorded by the eyetracker
Click image to enlarge.
eyetracker (the AlphaBio Eyeputer) is a specialised
video camera system mounted on a headset and coupled
to a computer. The infrared sensitive camera
records a close-up image of the eye while an image
processing board within the computer calculates the
position of the centre of the pupil. The headset
also includes a second camera (the Ďscene cameraí)
filming the scene in front of the head. Coordinates
of the each point in space that the artist is viewing
can be calculated in real time, and displayed either
as a cursor superimposed on the scene camera image,
or digitally stored on the computer for detailed analysis.
For this project we combined these recordings with
those from a hand movement sensor (Polhemus Fastrak
motion analysis system), so that we could also follow
the movement of the artistís pencil. This device
records the 3D position of a lightweight marker, attached
to the artistís hand or pencil, with the data also
digitally stored on the computer for later analysis.
While these eye and hand movements were being recorded,
the drawingís progress was filmed continuously with
a close-up video camera.
The temporal pattern of eye movements can be derived
from the digital data, as in Figure
1, or from a frame-to-frame analysis of the scene
cameraís recordings, as in Figures
2, 3 and 5.
The latter method, although restricted to a resolution
of 1/25th s, has the advantage of making evident the
locations in space of fixations and hand positions,
data which can then be used in conjunction with the
close-up video recordings.
E (Portrait of Nick)
This line was drawn about 8 minutes into the 5-hour
portrait. It depicts the back edge of the modelís
upper eyelid of the right eye. The only other
marks preceding this line on the paper were two eyelashes
of the same eye (Figure 2). The
line is about 5 cm long, concave downwards with a
changing curvature. It was drawn left-to-right
with the pencil stopping twice on the paperís surface
while the eye went back to look at the model Ė hence
the three sections E1-E2-E3 (1).
2: Line E, Portrait of Nick
Click image to enlarge.
2 provides the temporal sequence of eye and hand movements,
and summarises the corresponding values measured.
Using averaged values, one finds that the artist
drew a line 1.7 cm in length in 2.16 s before refreshing
his visual memory for 1.19 s. Fixations on the
paper during drawing were stable and located near
the start and slightly above the section being drawn.
Prior to E1, Humphrey practised the section by moving
his pencil without drawing several times over the
future trace, and towards the end of E3, his eye looked
away from the line to points about 5 and 10 cm to
the right and below his pencil. He finally returned
to E1-E2-E3 as his hand came to rest near his lap.
Line N (Luke 2 Portrait)
Luke 2 was a quick pencil drawing lasting 11.5 minutes,
and the line examined here which depicts the noseís
outline, was started 3.5 minutes from the start (Figure
3). Although slightly more complex than
the previous (the pencil left the paper momentarily
to start N2 and practised before N4) we still observe
the same draw Ė pause and refresh rhythm as before.
The averaged refresh rate of 2.10 s after a line of
1.6 cm is nearly identical to the previous case. Fixations
on the drawing are similarly stable or, for the longer
line N3, show one adjustment saccade from the start
to the end of that section. Nowhere do fixations
follow the pencil tip in smooth pursuit.
3: Line N, Luke2 Portrait
Click image to enlarge.
lines studied above are of a particular category:
single lines that define the shape and volume of the
portraitís main features: eyes, nose, ears, etc. Their
trace is unpredictable, in the sense that knowing
the starting point is insufficient information for
drawing them because angles and curvatures change
along their lengths. Furthermore, as they appear,
on the whole, in the early stages of a portrait, there
are no previous lines or marks to act as reference.
To achieve a precise rendering of such lines the artist
must refer back to the model every time his image
Lines H1-H6 and H9-H12 (Portrait of Nick)
T hese two lines, the last drawn in this portrait,
represent the outer contour of the hair on the modelís
right side. They are also the longest single
lines of the picture: 20 and 16 cm respectively (Figure
4). The first, of gentle uniform curvature,
was drawn in two consecutive strokes, H1-H4 and H5-H6,
with the hand resting at the lap in between. H5-H6
was then reinforced to become H7-H8. The second,
H9-H12, is straight at the top and gradually curving
at its lower end. For both these lines, the relation
between eye and hand is more complex than for E and
N (Figures 5 and 6).
4: H lines, Portrait of Nick
Click image to enlarge.
5: H lines, Portrait of Nick, graph for
Click image to enlarge.
6: Eye and hand positions during drawing of H
lines, Portrait of Nick
Click image to enlarge.
Prior to drawing, several long fixations on the model
(average duration 2.35s) alternated with shorter fixations
on the paper near the future trace of the line, during
which time the hand practised without marking the
paper(2). Drawing started at
point 1 and the pencil was then tracked to 2 and 3
with two small saccades. The hand then continued
to 4 but the eye left the trace for three further
fixations elsewhere on the picture.
This is a continuation of the previous line starting
with a small overlap. Drawing was preceded by
fixations on the picture and model, then the eye went
to point 5 as the pencil started but, instead of following
the line, further fixations proceeded elsewhere on
picture and included one fixation on the model. The
latter corresponded to a short pause of the hand about
3 cm before point 6, similar to the refresh fixations
seen in the E and N lines, although for H5-H6 the
eye did not return to the line when drawing resumed.
Preceded by several fixations on the model lasting
a total of 3.32 s, this line reinforced very precisely
the previous line. At the start of drawing,
the eye coincided with the pencil at point 7, but
left almost immediately for fixations elsewhere on
the picture while the hand drew the line.
A single short fixation on the model preceded the
drawing which started at point 9. The pencil
was tracked with a saccade to 10, then started leaving
the line at 11 for three fixations elsewhere on the
picture while the hand finished the line at 12.
With the last three lines, all sections below ear
level were made while the eye was looking elsewhere,
indicating that the painter did not need to fixate
the lines as they were being drawn or after they had
been finished(3). The H lines
are probably more predictable than E and N in the
sense that their curvatures, balancing the hairsí
tensile strength and the action of gravity, are more
"flowing" and uniform. Furthermore, the H lines
can be situated with respect to several previously
drawn lines representing that part of the face.
To achieve their precise rendering, the artist can
make use of these elements in addition to his visual
memory of the detail as seen on the model.
the painter, the drawing process is task controlled
Ė i.e. governed by the need to advance the portrait.
The two types of lines we selected for analysis inform
us on different aspects of this process.
The E and N lines illustrate the simplest cases of
a fading visual memory needing to be refreshed. The
painterís eye fixates on the line as it is being drawn,
and on the model while he is updating his memory.
He can draw about 1.6cm in about 2 seconds before
needing to refresh. Compared to results obtained in
other areas of visual perception and imagery, this
mental image maintenance time is exceptionally long.
Kosslyn (1994) suggests
that "the activity in the visual buffer should not
persist longer than about a quarter of a second".
However, in the painterís case, the information that
needs to be held in memory to continue an existing
line is essentially restricted to a single element
- the lineís angle. Furthermore, seeing the
line as it is being drawn materialises the mental
image and may aid in its maintenance (4).
The H lines denote a more complex eye-hand coordination
procedure. The painter can draw up to 16cm before
referring back to the model and he only needs to fixate
the starting point of the line being drawn. During
most of the drawing, his fixations centre on other
parts of the drawing not directly related to that
line (5). This would allow
for perception of the "picture so far" to become an
additional input into the drawing process, for example
by situating that line with respect to others previously
drawn. In a simpler eye and hand task also consisting
of seeing and reproducing a model (in this case, a
pattern of coloured blocks),
Ballard et al (1992) observed a similar dissociation
between eye fixations and hand position, the two only
coming together at key points of the task. Their
tests focused more on decision making and did not
involve the sort of fine motor tuning required in
drawing a portrait. Another observation on the
H line shows how complex this tuning can be.
It concerns the retracing of an existing line without
the aid of vision. Whereas drawing without looking
could be explained by motor commands based on a visual
mental image, retracing a 10 cm line perfectly about
10 seconds after the original, and without ever having
seen the original, suggests the presence of a motor
memory component to the drawing process. More
work with experts in drawing is required to elucidate
These two quite different types of lines occur in
their simplest forms during the first and last stages
of a portrait respectively. In between, all
the other lines exhibit a varying mixture of their
characteristics, i.e. the rhythm and timings of draw
Ė pause Ė refresh cycles, and the influence, as work
progresses, of the emerging picture itself. Portrait
drawing, at least for this painter, is a complex combination
of a fading memory image of the model and an increasing
presence of the emerging picture.
This line is also referred to in Miall
& Tchalenko, 2001 as Line 5,6,7. Back
The handís movements clearly indicated
that Humphrey was situating the future line with respect
to other lines already drawn: right side of the head,
ear, neck and a few strands of hair. Back
Another particularity about these
H lines is the speed at which they were drawn. The
pencil was moving at an average rate of 2.8 cm/s,
exactly three times faster than in the previous E
and N lines. Back
It is also possible that some Ďchunkingí
may be taking place, i.e. the painter, subconsciously,
divides the line he is seeing on the model into smaller
sections, and then attends to these one at a time.
However, even in this case, as the subdivision is
determined by the painterís experience of what he
can hold in memory before needing to refresh, the
dominant mechanism is still one of draw Ė pause and
5. In some cases, the drawing
hand is still within the peripheral field, and it
could be argued that the line is still seen. The painter,
however, holds his pencil in such a way that most
of the space before and after the actual pencil tip
is hidden from his view, and thus very difficult to
see accurately when focusing elsewhere. In most cases,
fixations are too far away from the pencil to be of
any use. Back
D.H., Hayhoe, M.M. Li, F. and Whitehead, S.D., 1992,
Hand-eye coordination during sequential tasks. Phil.
Trans. Roy. Soc. Lond. B, 337, 331-339.
Kosslyn, S.M., 1994, Image and Brain, MIT Press,
Miall, R.C. and Tchalenko, J.S., 2001, The
Painterís Eye Movements, Leonardo (Vol. 34, Issue 1,