Recent work on shadows


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After the publication of The Shadow Club (New York: Knopf, 2002; original edition Milan, Mondadori, 2000; reprinted as Shadows, New York, Vintage, 2004; translated in 7 languages; new Italian edition 2008) I published a number of papers on various aspects of shadows perception and representation. I am interested in perceptual phenomena (shadow illusions) but also in the interface betwen perceptual and conceptual representations of shadows. I rely on a large body of evidence, from ecology to phenomenology to the study of artworks.


A rare picture of a shadow from a plane’s trail. It’s early morning, the plane flies towards the sun, so that its trail is aligned with the sun’s rays. Picture taken from the Clochard, sailing towards Saint Tropez, July 2009. It nicely illustrate the notion of a shadow-body, or perceived three dimensional shadow.


The shadow cast from Burj Khalifa, as of today the tallest building in the world, seen from below. Picture taken in February 2012. The top is more than 800m above us. There is enough athmosphere between us and the top that does not get direct sunlight, and we can see the shadow against the background of the sky. Actually, the shadow is not cast in the sky, but unto the ground; we see it as continuing the building because of perspective shortening.

A missing shadow. Image Credit Roberto Casati, Paris, Septembre 2012

A missing shadow. Image Credit Roberto Casati, Paris, September 2012

Spot something missing? Shouldn’t the logo on the raquet cast a shadow? No. However, we argue in Casati R, Sorensen R, 2012,  that “Nonphysical visual objects generated by colour spreading are expected to cast shadows” Perception 41(10) 1275 – 1127.

An occluded shadow? Image credit: Roberto Casati, Paris, April 2011

An occluded shadow? Image credit: Roberto Casati, Paris, April 2011

Shadows are perceptual gestalten, so they should follow gestalt laws. Relatability makes the two tips of the pen appear as part of a single, occluded shadow. See: Casati R, 2012, “Some varieties of shadow illusions: Split shadows, occluded shadows, stolen shadows, and shadows of shadowsPerception 41(3) 357 – 360


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What does the puzzling picture on the left hand represent? (nb: no phtoshop!) And how could I manage to let my shadow pass under a carpet? An explanation can be found in the following article:

Casati, R., (2007), “How I Managed to Hide My Shadow”, Perception, 36 1849–1852 (‘Last but not least ‘ section). For more such pictures and a cute street performance video, check Marco Bacci and Marta Mellere’s site.


And which of the two above pictures is more convincing to you? Read an explanation in:

Casati, R., (2007), “The copycat solution to the shadow correspondence problem”, Perception, 37, 4, 495-503.


Other articles:


Casati, R., 2014, “Looking at images and reasoning about their content. The case of shadow depiction”. In Taylor, P., ed. Gombrich: Meditations on a Heritage. London: Paul Holberton, 139-153.

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Casati, R., 2014, Shadow-related concavity–convexity inversions reveal a very basic tolerance for impossible shadows. Perception, volume 43, doi:10.1068/p7727 

ART Shadow Purgatorio Lippi Orvieto

Casati, R., 2014, Stones, Shadows, Vision. In S. Njami, ed. The Divine Comedy – Heaven, Purgatory and Hell Revisited by Contemporary African Artists. Frankfurt a. Main, Museum für Moderne Kunst – Kerber Verlag, 50-65.

Casati, R., 2014, “Incident Light”. In: Larry Kagan, a retrospective. The Hyde Collection.

Casati, R., (2009) “Die Kunst des Schattenwurfs” (original ms. in English, German transl. by B. Kalthoff), in N. Bätzner, W. Nekes, E. Schmidt, eds. Blickmaschinen. Köln: DuMont, 101-106

Casati, R., (2008), “Are shadows transparent? An investigation on white, shadows and transparency in pictures“, to appear in Res.

Casati, R., (2006), “The cognitive science of holes and cast shadows”, Trends in Cognitive Science, 10, 2, 54-55.

Casati, R., (2005), “Shadow tales of knowledge and power”, in T. Sadowsky, ed. 2005 Shadow Play – Schattenspiel. Odense: Kunsthallen Brandts Klaedefabrik. 2

Casati, R., (2004), “The shadow knows: a primer on the informational structure of cast shadows”, Perception, vol 33, 11, 1385-1396.3

Casati, R., (2004), “Methodological Issues in The Study of the Depiction of Cast Shadows”, Journal of Aesthetics and Art Criticism, 62, 2, 163-174 .4

Casati, R., (2003) “The availability of large size from shadow: looking for hidden assumptions”, Perception, 32, 1021-1023. 5

Casati, R., (2003), “Towards a cognitively oriented database of early shadow depictions“. Poster for the conference Shadows – From Art to Neuroscience, Rovereto — MART (2003-11) 6

Casati, R. (2002d) “The secret of shadow”. The Secret of Light and Shadow, Frankfurt: Deutsches Architektur Museum.

Casati, R. (2001a) “The Structure of Shadows”, in A. Frank, J. Raper, and J.P. Cheylan, Time and Motion of Socio-Economic Units, London: Taylor and Francis, 99-109.

Some unpublished material on shadows.

It took years of patience, but I eventually managed to get a picture of the shadow of a plane which is about to land, from inside the plane.


Februay 2012, Landing at Orly Airport

A cognitively oriented database of early shadow depictions (with the assistance of Valentina Rachiele)(Online soon).

What happens to the shadow, if you outline it?

What happens to the shadow, if you outline it?

Last but not least, an example of shadow death: what happens to a shadow, when you outline it? You can see the phenomenon in a clip from director Werner Weick’s  Dalla parte dell’ombra”, a RTSI documentary in which we explored the streets of Florence in search of intriguing shadows, and had shadow performer Francesca Bizzarri recreate for us some of her art at the Teatro della Limonaia. (Spotted also here.)

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