Leonardo

Holographic Chiaroscuro: Figures in Virtual and Pseudoscopic SpaceAuthor(s): Paula DawsonSource: Leonardo, Vol. 41, No. 3 (2008), pp. 302-303Published by: The MIT PressStable URL: http://www.jstor.org/stable/20206610 .

Accessed: 12/06/2014 18:05

Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .http://www.jstor.org/page/info/about/policies/terms.jsp

.JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact support@jstor.org.

.

The MIT Press and Leonardo are collaborating with JSTOR to digitize, preserve and extend access toLeonardo.

http://www.jstor.org

This content downloaded from 195.78.108.40 on Thu, 12 Jun 2014 18:05:48 PMAll use subject to JSTOR Terms and Conditions

3

Holographic Chiaroscuro: Figures in Virtual and Pseudoscopic Space

Paula Dawson. College of Fine Arts, The

University of New South Wales, PO Box 259 Paddington 2021 NSW Australia.

p.dawson@unsw.edu.au

In two recent holographic stereograms

Shadowy Figures [ 1 ] and Luminous Presence [2], I have animated the dark ness and light within the spatial volume of the image to lend a sense of complex temporality to a figure. The type of com

plex temporality I am hoping to evoke stems from a particular example de

scribed by Michel Baxandall [3], Tie

polo's drawing of a Roman soldier.

Tiepolo's drawing approach is to intro duce spatial anomalies by unifying the

composition with one overall lighting schema into which are embedded smaller zones rendered as though lighting were in a completely different position. In the case of the Roman soldier drawing, the

entirely different zone of shading nested in a section of drapery leads to the am

biguous interpretation of the leg's being in two possible positions. Pictorially the transition between the two models is

completely seamless, yet in the viewer

there is a constant shifting between the alternate lighting models, thereby ex

tending the actual time of engagement with the image and precluding a simple and finite location for the figure, both

spatially and temporally. Pictorial styles which involve anomalies in light and darkness have long been used in two

dimensional media (such as drawing, fresco, and painting) by artists, to engen der a greater sense of familiarity and

presence of the subject. I have been

seeking parallel and alternative means of

accomplishing this effect through de vices available though the inherent prop erties of the medium of the digital holographic stereogram.

The way in which a beholder interacts with an animated holographic stereo

gram is quite open-ended. Unlike film animation, in which the rate of frames is

predetermined, the sequence linear and

the beholder stationary, the animation

frames of a holographic stereogram are

all visible simultaneously, enabling the beholder to sample the animation by entering and walking though the space before the hologram film plane. The

pace of the beholder's steps determine the speed at which the frames are seen and their left/right direction determines

the beginning and end of the sequence. The animation can be paused at any

point by the beholder's becoming sta

tionary. Due to the direct correspondence be

tween the viewer's spatial location and

the specific pairs of frames which are channeled to their eyes it is possible to build the illusion of a static three dimensional scene, such as in the portrait series of Chuck Close. The opposite effect is also possible, that of destroying the three-dimensionality by moving the

subject elements in every frame. This has been used by Eduardo Kac in work titled AdHuk in which scattered mobile letters coalesce to form the word AdHuk

when the beholder occupies one specific position [4]. In both holographic stereo

grams, Shadowy Figures and Luminous

Presence I combined static figures (to

ensure the scene would read as a three

dimensional place) while animating the

lighting and darkness surrounding them. However, as the viewer of the holo

graphic stereograms is likely to walk and then pause, since this is the way most

other wall based work is viewed, it is

possible to portray major differences in the lighting and darkness of a single stationary scene, treating each frame as a

complete work. The lighting and dark ness of the subject of the hologram can undermine or support the experience of

the image as occupying the present

tense, which its space suggests.

Through changes in the 81,920 hogels (holographic pixels), which comprise Shadowy Figures, I investigated three distinct approaches to using darkness [5]. Dividing the viewing space into three

zones across the horizontal axis (know as

three-channel and visually resembling a

wipe) enabled me to position different treatments of darkness employed by Giotto, Masaccio and da Vinci side by side on a single figure. The particular

examples are drawn from Michael Bax

andalPs book Shadows and Enlighten ment: Giotto, Joachim and the Shepherds fresco, Scrovegni Chapel, Padua; Ma

saccio, Baptism of the Neophites, fresco,

Santa Maria del Carmine, Florence; Leonardo da Vinci, Drapery Study, brush drawing on brown linen, British Museum. To accentuate the differences

between the treatment of light and dark ness in each of these works I chose the dominant feature of each and applied it to a single scene of a static figure located

in an ornate niche.

My interpretation of Giotto was to po

sition the origin of the light directed at the figure at the point of view of the

capture camera. In this way wherever the

viewer stands they seem to illuminate the

figure while modeling shadow increases the farther it is from the angle of obser vation. The lighting on the figure in the

hologram is mobile, and originates out in the space in front of the holographic plate. The awareness of the correspon dence of the light source on the figure to the position of the beholder builds

slowly as the beholder sees more and

more of the animation. Masaccio's light

ing treatment was a fixed point- source

to the top left, slightly behind the picture plane, with cast shadows falling diago nally. It is interesting that this familiar

lighting formula of Masaccio's, which is

commonly employed to convey clearly a

Fig 1. Luminous Presence, holographic stereogram, 1000 x 1500 mm, 2007.

(? Paula Dawson. Photo ? David Braun.)

302 LEONARDO, Vol. 41, No. 3, pp. 302-303,2008 ?2008ISAST

This content downloaded from 195.78.108.40 on Thu, 12 Jun 2014 18:05:48 PMAll use subject to JSTOR Terms and Conditions

sense of three-dimensionality in 2D me dia (such as the ubiquitous shadows un der pull-down menus) can be objectified in the context of Giotto and Leonardo da

Vinci's very different approaches. Fi

nally in my interpretation of da Vinci I used a curved reflective strip to diffuse

light over the entire figure from a posi tion in front of the picture plane, and as a

special feature I used a 'negative light', i.e. a source of darkness, which was cre

ated using Maya, directed from the right hand side onto the figure.

In Luminous Presence (pictured in Fig 1. and Fig 2.) I developed a more inte

grated composition in which specific local

ised lighting changes were nested within an

overall figure/ground reversal from light on

a dark background to dark on a light back

ground [6]. I estimated, by pacing and

pausing in front of a 1500 x 1000mm wall

space, that the 2,496 frames would be seen

over a period of between 6 and 10 seconds

[the You Tube video Paula Dawson holo

gram SIGGRAPH bears this out], whereas,

had the same renders been shown as a typi cal cinema animation at 24 frames a sec

ond, it would have taken around 100

seconds There are, returning to Tiepolo's

model, two elements in the scene which

physically move: the overall unifying light ing of the oblong flecks of gold which fill the spatial volume and in cross -hatching

style at different planes move diagonally, and the transparent figure in the foreground which fragments into stripes and disap

pears. The diagonal movement of the

flecks of gold avoid the associations of

up/down motion with hail and rain and

which would cause a viewer to conclude

that the correct direction of motion was the

one in which the particles move down. As

can be seen in Fig 2., the repetition of the

same figure in a more solid form through out the composition enables the viewer to

become very familiar with the spatiality of

the figure from many spatial orientiations.

Despite the interesting things which can be seen through the transparent figure, such as

in Fig 2. where it is possible to see the

inclined head of a further replica of the

figure through the lower part of the trans

parent figure's face, thanks to the spatial information registered in the viewers mind

by the four solid versions of the figure, it is

possible for the viewer to override the im

portance of the visual information passing

though the figure and to read the figure as

solid. It is also possible for the viewer to

interpret the far side of the transparent

figure as the near side - thus spatially turn

ing the figure inside out. This form of

switching between the virtual and the

pseudoscopic as alternate interpretations of

the image which is intrinsic to the practice of holographic image- making also seems

to be a key element in extending the picto rial vocabulary to enable complex tempo

rality in holographic stereograms. [7] The use of transparency in holographic stereo

grams can lend a similar complex tempo

rality to a figure as shadows did in

Tiepolo's drawing.

3

Fig 2. Luminous Presence, holographic stereogram, 1000 x 1500 mm, 2007. (? Paula Dawson. Photo ? David Braun.)

References and Notes

1. <http://www.shadowyfigures.com>

2. SIGGRAPH 2007 A Computer Graphics Annual Conference Series, 2007 a publication of ACM SIGGRAPH, Electronic Art and Animation Cata

logue, Art Gallery: Global Eyes page 262.

3. Baxandall, Michael 1995, Shadows and Enlight enment, Yale University Press, New Haven &

London.pp 48,49.

4. <http://www.shadowyfigures.com>

5. Zebra: US Patent #6,330,088. Method and appa ratus for recording one-step, full-color, full paral lax, holographic stereograms (Holzbach, Klug); M. Holzbach.

6. <http://www.pauladawson.com.au>

7. <http://www.library.unsw.edu.au/~thesis/adt NUN/public/adt-NUN20020418.103955/>

Transactions 303

This content downloaded from 195.78.108.40 on Thu, 12 Jun 2014 18:05:48 PMAll use subject to JSTOR Terms and Conditions