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| Image credit, JVC Creative Commons |
On a cool early autumn day in Bellingham, WA, in 1965. The Society of Photo-Optical Instrumentation Engineers—SPIE staff were still in the glow of celebrating their 15th anniversary when they published Frederic Billingsley’s paper, Digital Video Processing at JPL. They didn’t know it at the time, but it was a landmark publication and firmly established the name and characteristic of The Pixel.[l]
The larger part of the job of digital picture processing turns out to be the necessary bookkeeping involved in getting a picture of, say, 600,000 picture elements (pixels) processed in a system having only 65,000 bytes of core. (A pixel is a sample of the picture such that the highest spatial frequency contained in the picture is sampled with two pixels. The system is designed such that intensity levels may be defined to one part in 256 and thus be described by 8 bits. A pixel and a byte are therefore synonymous in this usage.) —F. C. Billingsley, “Digital Video Processing at JPL,” SPIE, Vol. 0003, 1965
Forty years later, in 2006, SPIE published Richard Lyon’s extraordinarily researched essay on A Brief History of ‘Pixel’ — the birth of the name Pixel by Billingsley.[ii]
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| Frederic Crockett Billingsley at JPL (Source: Richard Lyon) |
Not that the doughty pixel didn’t have competition. IBM and Bell Labs preferred to use pel, picture element, as the smallest addressable element in a raster image. Lyon’s paper traces the competition between the use of pel by IBM and Bell Labs and the use of pixel. Pel is more logical and easier to use, but pixel is just more fun. The pixel had plenty of competition, such as points, point array, spot, raster elements, picture points, and others.
Adopted by the International System of Units (si), the pixel, abbreviated as px, is used for measurement in graphic and web design (and before that, typography), it is equivalent to roughly 1/96th of an inch (0.26 mm). Developers used it to make sure a given element will display as the same size no matter what screen resolution views it.
In 2013 Google had the audacity to try and co-op the name pixel and applied to their smartphone.
And then, in August 2021, cofounder of Pixar, Alvy Ray Smith, published his book, A Biography of the PIXEL.[iii] Alvy says that the bit became the universal medium, and the pixel—a special packaging of bits—conquered the world.
Once we enter the digital world, says Alvy, almost every picture in the world is constructed of pixels—images on a smartphone, Mars Rover transmissions, app interfaces, book illustrations, and videogames. Alvy says that the pixel is the organizing principle of most modern media, and he presents some uncomplicated but insightful ideas that combine the dazzling varieties of digital image-making.
In his book, Alvy starts his story of the pixel’s development with Fourier waves, follows that through Turing machines, and arrives at the first digital movies from Pixar, DreamWorks, and Blue Sky. Today, says Alvy, almost all the pictures we meet are digital—facilitated by the pixel and separated irretrievably from their media; museums and kindergartens are two of the last outposts of the analog. Alvy is a great storyteller. In the book, he charmingly and invitingly explains how pictures that are composed of invisible stuff like data become visible—that is, how digital pixels convert to analog display elements.
Taking the particular case of digital movies to represent all Digital Light (his term for pictures constructed of pixels) and drawing on his decades of work in the field, Alvy tells the story from multiple angles—art, technology, entertainment, business, and history. A Biography of the Pixel is a wonderful read for anyone who has played a videogame, seen a movie, or watched a video on a smartphone and wondered about where and how it came to be.
But what IS a pixel? Wikipedia says: a pixel, pel,[iv]; or picture element[v]; is the smallest addressable element in a raster image or the smallest addressable element in an all-points-addressable display device; so, it is the smallest controllable element of a picture represented on the screen.
But a pixel can be subdivided and theoretically infinitely. And the subdivisions are controllable, although they may not be visible to the naked eye; Epic’s epic Nanite demo proved that.
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| Subdivided pixels—this is what 20-million triangles look like at 4k—each color represents a different triangle (Source: Epic Games). |
And, referring to Alvy Ray’s book, pixels are not little squares, even though they are frequently represented that way. The word pixelation particularly irks him because it has institutionalized the misconception of what a pixel is. (Side note—pixelation is a term popularized by animators, including Norman McLaren and Grant Munro, for stop-motion animation.[vi]; and is not the same thing as pixElation)
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| Seurat’s Parade de cirque, 1889 (Source Metropolitan Museum of Art, Public Domain) |
Alvy says pixels have no shape and are just samples taken (hopefully) at a regular interval, like a grid. They have no dimension, no width, weight, or even color; in fact, you can’t even see them; they are a mathematical construct. They have a weighting, a number that can represent a color or shade of gray. And they can be assigned a location (x, y) in real-world dimensions, computer dimensions, or screen dimensions.
This writer has yet another definition of the pixel: It is the point of contact in the man-machine interface where information is transferred.
A pixel can be thought of as a letter or punctuation mark, and the screen it is buried in as a book. Individually or in concert with its companion pixels, it conveys meaning and purpose. It can be transient or permanent. It can be personal in the form of an AR retail impingement or communal in the form of a video wall and every imaginable manifestation in between. Pixels can even be simulated in the brain for the blind with an implant in the visual cortex.[vii]
Pixels have been with us since the first reproductions, which can be traced to cave drawings and epitomized by Georges Seurat and Paul Signac. They became digital in the 1950s as part of the missile defense system in North America, NORAD, and today we literally could not live without them.
I’ve been chasing pixels since the 1960s. I’ve loved many I’ve seen, been scared by others, and questioned the creators’ s motivation on still others. In the most extreme sense, you could say the Sun is a pixel in the universe’s canvas.
May the pixels be with you.
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References:
[l] F. C. Billingsley, Digital Video Processing at JPL, (1965) in Eugene B. Turner (ed.), Electronic Imaging Techniques I, Proceedings of SPIE, Vol. 0003, pp. XV-1–19
[ii] Lyon, R. “A brief history of 'pixel, (10 February 2006)Proc. SPIE 6069, Digital Photography II, 606901; https://doi.org/10.1117/12.644941
[iii] Smith, A. (Aug 03, 2021), A biography of the PIXEL, The MIT Press, 560 Pages, ISBN 9780262542456, https://mitpress.mit.edu/books/biography-pixel
[iv] Foley, J. D.; Van Dam, A. (1982). Fundamentals of Interactive Computer Graphics. Reading, MA: Addison-Wesley. ISBN 0201144689.
[v] Rudolf F. Graf (1999). Modern Dictionary of Electronics. Oxford: Newnes. p. 569. ISBN 0-7506-4331-5.
[vi] Gasek, T. (January 17, 2013). Frame by Frame Stop Motion: NonTraditional Approaches to Stop Motion Animation, Taylor & Francis. p. 2.
[vii] Juskalian, R. (February 6, 2020), A new implant for blind people jacks directly into the brain: Researchers have successfully bypassed the eyes with a brain implant that allows rudimentary vision, MIT Technology Review, https://www.technologyreview.com/2020/02/06/844908/a-new-implant-for-blind-people-jacks-directly-into-the-brain/