Holograms from Eadweard Muybridge’s Studies of the Human Figure in Motion
Eadweard Muybridge is chiefly remembered for his extraordinary work with the photography of movement. He was the first person to prove that a horse at full gallop takes all four of its hooves off the ground at one point in its stride.
Muybridge was given sponsorship by the University of Pennsylvania, where he undertook his most famous project. In one year he took more than 20,000 photographs of men, women, children, animals and birds, and in 1887 the photographs were published as a monumental work of 781 folio-sized plates, entitled “Animal Locomotion”. It remains to this day the most comprehensive analysis of movement ever undertaken, and is still used widely as a reference source for illustrators and artists.
What is less known about Muybridge’s photographs is that they have latent parallax: when a sequence of his photographs is presented as a short animation, the motion parallax is perceived:
In this example, the observed three-dimensionality of the two figures, especially details such as the woman’s dress, is quite apparent, even though the parallax is not stereoscopic, but temporal (motion) parallax.
The stereoscopic parallax is seen clearly when two frames of the sequence are removed and put together side by side:
Free-viewing the Muybridge photographs reveals that consecutive prints in the sequences are stereoscopic, producing clear three-dimensional images. In the many thick books written about the Muybridge photographs there is very little (if any) mention of the fact that these sequences of images are stereoscopic.
The fact that the photographs have parallax information in them is a direct result of the way in which they were taken. Muybridge was working several years before the invention of the cine-camera, so in order to expose his photographic plates in quick succession he designed a method by which a number of individual cameras were triggered by the subject passing in front of each camera in turn. Because the cameras were arranged in a line a few inches apart, they recorded different perspective views of the subject.
A total of 20 holograms of selected Muybridge sequences were made as part of the PhD thesis ‘Aspects of Spatial and Temporal Parallax in Multiplex Holograms’ at the Royal College of Art in 1994. Each of the holograms combines both the stereoscopic parallax and the motion parallax that is latent within the photographic sequences.
The “Arabesque” was the first hologram in the Muybridge series. In the original Muybridge plates this is an austere image, vaguely reminiscent of Gray’s anatomical drawings, while the pose is redolent of Leonardo da Vinci’s famous drawing the ‘Vitruvian Man’ (also called the ‘Canon of Proportion’), of a nude man framed in a circle and a square.
Because Muybridge shot each of his sequences against a grid of lines in the background, it is possible to see very accurately the degree of motion that the subject has undergone from one frame to the next. This proved very valuable in analysing the relationship of the stereoscopic parallax (generated by the different views from each of the cameras, and governed by the distance between the cameras) to the temporal parallax (generated by the subject’s rotational motion from one photograph to the next) in the sequence.
Not a great deal has been written about temporal parallax (or motion parallax) in books about stereoscopic photography or holography. However, N. A. Valyus, in his book ‘Stereoscopy’, defines temporal parallax as:
“The displacement of any image point which occurs in a time corresponding to the visual inertia of the eye relative to the image of the moving fixation point”.
Perhaps a more straightforward description would be: “how a one-eyed man still knows that the world is in 3D by moving his head from side to side”; that is, the ability to perceive the solidity of objects and their spatial relationships by their relative displacement, rather than by stereoscopy.
Temporal parallax might be described as “memory parallax” because, whereas stereoscopic parallax is derived from a comparison of two views both seen at the same moment with two eyes, temporal parallax is perceived by comparing the view seen by the eyes at one moment in time with the view an instant later.
In the “Arabesque” hologram, the fact that the figure is standing on one leg, anchored to the same spot throughout the sequence, means that this portion of the scene contains only stereoscopic parallax, caused by the lateral displacement of the cameras used to record the sequence.
In the sequence, the figure moves his right leg clockwise through 180 degrees. This may be regarded, for the purpose of parallax analysis, as two progressions of 90 degrees each. What is fascinating is the very different way these two motions are interpreted by the brain.
If one examines frames 4 and 5 as a stereoscopic pair, one can see the hyper parallax distortion on the outstretched leg. In the first part of the rotation, although most of the other image points in the scene fuse together well, those image elements (the foot and leg) where the stereoscopic parallax has been added to the subject’s motion parallax appear to go deep into the scene, away from us (so that the solid back wall looks like a net with the leg extending through and beyond it).
As the figure continues to rotate his leg through a further 90 degrees (clockwise), the subject’s motion parallax is again combined with the stereoscopic parallax in our perception of the image:
If one examines frames 8 and 9 as a stereoscopic pair, one can see the hyper parallax distortion on the outstretched leg. Resting one’s gaze on the extended foot, and comparing its position relative to the grid backdrop, one can discern that the limb is stretched out towards the observer, like a tiny foot at the end of an insect-like leg.
Although the motion of the leg is constant, in a clockwise direction, its path across the visual field changes from right-to-left to left-to-right. This difference in the relative displacement of the local image elements (the leg and foot) relative to the rest of the scene causes the leg to appear to go deeper into the scene at first (images 4 & 5) but then to come forward (images 8 & 9), stretching out of the scene. The temporal parallax in the scene has directionality, which can be “with” or “against” the direction of stereoscopic parallax. The first part of the figure’s rotation works to extend the limb deep into the scene, away from us (so that the solid back wall looks like a net with the leg extending through and beyond it), whereas the second part of the figure’s rotation works to extend the depth towards us, and the leg stretches right out into the viewer’s space.
The Muybridge sequences were made from left to right, with each new image exposed to the right of the previous image. This is the correct direction for a sequence that is suitable for orthoscopic viewing of stereoscopic pairs (parallel free-viewing). If the subject motion is equal to the progress of the camera and going in the same direction, it will be as if both were standing still. The stereoscopic parallax will be diminished or cancelled out by the temporal parallax, and the subject will appear flat in that part of the scene.
Understanding that a camera movement, a dolly or track shot laterally past the subject, has an effect on the perceived dimensionality of the subject is critical to adding effective realism to the scene. Even a simple shot of a person talking to camera can be made much more compelling if there is a subtle tracking shot moving from left to right past the subject (as opposed to the opposite, from right to left); likewise, a subject rotating clockwise to a camera in a fixed position will provide more realism than an anti-clockwise motion.
Temporal parallax in film, video and television can be as engaging to the viewer as stereoscopic parallax (in 3-D movies), and some of the best examples of motion parallax appeared in the years following the completion of the thesis ‘Aspects of Spatial and Temporal Parallax in Multiplex Holograms’ at the Royal College of Art in 1994.
The best example of motion parallax used in a feature film was in The Matrix in 1999, which introduced (or rather re-introduced) the cinematic effect ‘Bullet Time’.1
In order to avoid subject motion moving counter to the direction of orthoscopic parallax, most examples of ‘Bullet Time’ are of a ‘frozen moment’ (also known as a ‘time slice’), where a set of cameras are all triggered to expose at the same instant, so as to freeze all subject motion.
“Arabesque” (above) and other holograms were exhibited in a one-man show at the Museum for Holography & New Visual Media in Germany. Another hologram, of a nude man riding a horse, was selected for the show “Towards a Bigger Picture”, which was also shown at the Tate Gallery Liverpool and the Victoria & Albert Museum, and is now in the V&A’s permanent collection.
Notes
- Stephen Herbert notes in
his blog (9 March 2009) that Eadweard
Muybridge was the first to invent ‘Bullet Time’, the cinematic
effect used in films such as ‘The Matrix’ (1999). ↩
Bullet Time, (almost) 1884
“According to Wikipedia: [Bullet-time] is the effect used in The Matrix, and other movies, and is achieved roughly the same way as Muybridge set up his shots. In effect, however, Muybridge had achieved the aesthetic opposite to The Matrix's bullet-time sequences, since his studies lacked the dimensionality of the later developments.
But not in this example, which certainly has dimensionality.
My crude animation of Animal Locomotion Plate 527, Spanking a child, will I hope demonstrate that the technique generally known as "bullet-time" and made famous by The Matrix (1999), has a long history. This animated sequence (two of three series of the same subject, joined together) was taken by Muybridge during his sessions at the University of Pennsylvania, in 1884-5. But this wasn't, apparently, his first experiment with the technique. An article in the New York Times in 1881 (February 19) entitled 'Instant photography; results of the California experiments' described an earlier session, for a specific purpose.
Mr. Muybridge, once in the studio of Mr. Perry, watched with interest the artist endeavoring to outline the picture of a California coach and four. He had Mr Muybridge's pictures as a guide. But these were broadside views, and he wanted a quartering view. Mr Muybridge hastened back to Palo Alto, arranged five cameras in a semicircle and concentrating upon one point, galloped a horse over the point where the electric current was completed, and produced a perfect picture of a horse at fullest speed, as seen from five different points of view, all at the same instant of time and while, of course, the horse was in one and the same position. Now, an artist with these pictures as guiides can draw a horse in any position desired.”
— Stephen Herbert
- See also: ‘Who Invented Bullet Time’
- See also: ‘A Brief History Of Bullet Time, Aka The Matrix Effect’