[syndicate] The Sondheim effect*

[Alan Sondheim]

The Sondheim effect*

Working with film twenty years ago, I discovered that if stereographs
(which are mostly late 19th-early 20th century photographs viewed through
a stereoscope, giving the viewer a three-dimensional image) were rephoto-
graphed on movie film, alternating left and right - upon projection, a
three-dimensional effect was clearly visible, even though both eyes
perceived the left and right viewpoint. In traditional stereoscopy, the
left eye perceives the left-taken image, and the right perceives the
right-taken one. In other words the three-dimensionality is synchronic-
ally, spatially, encoded and the mind reconstitutes the scene. In the
Sondheim effect, the encoding is diachronic; both eyes perceive both
images in quick (16-24 fps) alternation. The result should be 'something'
like a back-and-forth shuddering, which does occur, but it is accompanied
by a three-dimensional illusion which has varying degrees of depth,
depending on the original image - clear foreground/background information
tends towards the greatest illusion.

(It's been pointed out many times that it's possible to create depth by
watching a soccer game, for example, with a slightly dark neutral density
filter over one eye. This creates a small processing lag, so each eye
processes at a different rate, hence is reading slightly different images
from the playing field. Now if the ball moves horizontal- ly, it's seen
simultaneously in two different positions, against a more or less constant
background, and appears, again slightly, to jump out from the screen.)

In three-dimensional unpacking, the mind fills in synchronic or diachronic
digital information - discrete images - to recreate the plenitude of the
real, in a sense 'being there.' Think of this as a gestural operating -
given limited information, filling in the blanks, as if vision were active
(which it is) and gestural, as if vision originated primarily from the
perceiver. (This is clear in vision studies, the work of Marr decades ago,
color vision theory, etc.)

Since the analogic is fundamentally continuous, 'of the real,' it might
also be considered, in this case (and the case of color theory etc.) a
kind of suture or bandaging - what are really, inherently, disparate
images - either from photographs or from perception of physical reality -
are combined into a simulacrum of a continuum of spatial depth. Stereo-
graphs are an example of a production involving simultaneity (space);
alternation is an example involving succession (time). This is of course
far too neat and I'm positive would break down on the cog-psych or neuro-
physiological level. So the Sondheim effect in this regard is nothing more
than a curiosity, the sort of thing one might read in Mind Hacks. On the
other hand, the idea that succession can imply a re-reading or reconsti-
tution of simultaneity has interesting phenomenological implications, as
anyone familiar with Husserl on internal time-consciousness knows. The
following video has the _slightest_ Sondheim effect among the runners; and
even when trying, I've never been able to get the sharpness necessary to
reproduce it in video at all. Now with HD, it should be easy to do and it
would be interesting to see the results of a complete narrative movie
presented in such a manner - would the shuddering finally become invisible
as vision synchronized itself to temporal collapse?

http://www.asondheim.org/roughrace.mp4

* Of course, naming the effect after me quickly gives way to the realiza-
tion that there must be thousands of experimental studies of just such
things; it's more than obvious. Viewing alternations is standard in lang-
uage and motion studies; the only difference here is that the alternating
images are from slightly different viewpoints.