Ken Jacobs, The Pulfrich Effect and Time Based Stereoscopy

ken460Ken Jacobs with wife Flo Jacobs

At a time when film industries are currently working on perfecting 3D cinema delivery, numerous guides and projects aim at perfecting the image’s illusion and making the viewing experience as smooth as possible. In commercial entertainment contexts this makes sense and meets demands expected by many audiences. However, it occludes, to some extent, the potential for artists to use stereoscopic techniques to work against cinema’s perfect illusion and test our relationship with moving-images. One such artist who has been working in this field for numerous decades is Ken Jacobs. Based in the US, Jacobs has experimented with different stereoscopic technologies since the 1960s and, now in his 80s, utilises new digital technologies to continue that work.

As part of their current exhibition on Cinema & Painting, The Adam Art Gallery in Wellington screened two of Jacob’s stereoscopic films at the local Lighthouse Cuba cinema. Both films push the limits of how stereoscopy can be used to produce three-dimensional space and both films draw upon early cinema to reimagine how cinema might be perceived. Neither film makes use of traditional stereoscopy whereby two flat images with a parallax separation are created at exactly the same time and are then brought together to create the illusion of depth. Instead, the images are separated by time. However, each film does makes use of the fundamentals of stereoscopy: by creating two different images for each eye and using viewing technologies to bring those images back together, they seem to produce one image with additional depth qualities.

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The first film, Opening the Nineteenth Century: 1896 (1990), incorporates a fairly unique exhibition process with its use of the Pulfrich effect. Developed as a theoretical study by Carl Pulfrich in 1922, the Pulfrich effect works on the basis that if one eye is covered with a filter when watching moving images, each eye will receive visual data at slightly different times. As Ken Jacobs put it in his video introduction to the event, one eye sees the current image and the other eye sees an image from the recent past. When the images being viewed incorporate horizontal motion, the different images received by each eye come together to create the sensation of depth. In Opening the Nineteenth Century: 1896, Jacobs put this to the test by showing footage of early Lumière films that constantly incorporated cameras in motion: mainly views from moving boats and moving trains. When viewed without the filter, we have a record of some of the earliest moving-images. Their black and white, often over-exposed and/or deteriorated quality gives us a glimpse of a past that is now gone. The objects and figures that appear in the footage are ghostly incarnations gesturing to us from a place that we will never know, made all the more distant because no sound has been added to the footage. When you place the filter over one eye, an eerie sense of depth suddenly appears. It is not the same sharp illusion of depth that can be found in contemporary digital stereoscopy, but there is a subtle shift in which the clear position of the screen’s plane disappears and the material elements of the footage float in a less determined space. Much of the footage incorporated by Jacobs has water at the bottom of the space. It laps towards us and heightens the sensation of fluid space that can reach into the auditorium. At various points the footage is placed upside down. Although no obvious reason for this choice is provided, it acts as a reminder that there is a highly mediated cinema mechanism functioning between us and these ghosts of the past.

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The second film, The Guests (2013), uses another technique entirely. Taking an early Lumière film that was gifted to Jacobs and his wife, Flo, images are once again separated by time but projected to audiences in an entirely different way. Flo painstakingly cut apart the different frames in the film and pasted them onto glass slides, alternating the frames so that every odd frame could be used for one eye and every even frame could be used for the other eye. Initially these were displayed in a carousel so that audiences could receive the different images for each eye simultaneously. Later, they were converted into DCP files so that they could be displayed on 3D capable screens. In this instance, the odd frames arrive at one eye and the even frames arrive at the other eye through 3D glasses. Because the 3D glasses filter the images so that each eye receives only one set of images, the eyes are then able to fuse these images into one image.

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The initial film was of a wedding party in Paris climbing the steps of the church. Because the people in the film were moving roughly in one direction, the alternating frames are mainly the same but with a slight change in position of the characters. This allows the eyes to be tricked in to believing that they are each seeing the same image but shot from slightly different positions. In this way, the eyes create an illusion of stereoscopic depth. Because objects in the background have not changed position, the process is not dissimilar to the production of stereoscopic depth in traditional 3D films where some objects are placed at a zero parallax point (no separation between them) and others seem to come towards the audience or recede away from the audience depending on the level of parallax separation between them. Of course, the changing temporal relations and the unruly movement of characters in the original film means the creation of depth in The Guests is not a perfect process. Instead, the result is another set of eerie images where the depth relations of some characters and objects pop out and shift in unexpected ways. During the course of The Guests, Jacobs slows down the images so that what was once a one-minute film is now stretched to around 70 minutes. Although this extended length puts huge demands on the attention span of the audience and some argument might be made in favour of a shorter exercise or the display of the film in a gallery where audiences can choose to come and go as they please, The Guests is extremely effective in the way it asks us to reconsider the visual illusion of stereoscopy and the illusion that is at work in all cinema. The way in which characters’ limbs and heads seem to pop out or recede behind other body parts illustrates the false wholeness that is projected in all cinema, but often emphasised in 3D cinema.

Perhaps the most powerful aspect of this programme of Jacobs’ work was the emphasis on time. The video introduction made it clear that this is an enduring interest of Jacobs and his wife Flo. Their ability to bring forth a consideration of time is what is often missing from the focus on spatial relations that so often dominate discussions of 3D media.

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1 Comment

  1. Goodbye to Language 3D: Painful Sight | miriamruthross

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