A Biography of the Pixel, book review: The life and times of 'digital light'

From cave paintings to Toy Story, via expeditions to Egypt, Russian gulags and a hundred other directions that manage to be both weirdly relevant and usually fascinating, this is the physics and family history of everything that goes into images on screens. 

Pixels aren't the tiny glowing dots on your computer screen (strictly speaking, we should call those display elements). Instead, they're a sample of a visual field at a single point that has location and colour. Or more eloquently, they're the invisible digital bits that represent what Alvy Ray Smith calls 'digital light' (the book's original title) -- the technology that lets you see digital text, drawings, photographs, videos, movies and TV shows, because they're made visible by computation. The pixel, he suggests, is a "profound and abstract concept that binds our modern world together". 

Smith should know: the co-founder of Pixar, he also helped create the field of computer graphics, developing everything from sprites to the HSV colour space model (and he sold his second company, Altamira, to Microsoft where it became the basis of Microsoft's multimedia authoring tools like PhotoDraw, and became Microsoft's first graphics fellow).  

Smith has spent the last decade researching and writing A Biography of the Pixel to explain the concepts behind the digital images on the screens we look at all day long, because hardly anyone knows what they really are or how they work (and even experts in the field rarely look at the big picture of how it all fits together). In fact, even Smith didn't know before he started work on the book that the first pixels date back to the first computers. He goes back even further, to the first animation -- a boar drawn on the wall of a Palaeolithic cave with extra legs, so in the flickering firelight it looked as though it was running. 

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There's a lot of mathematics behind computer graphics, and there's a bonus set of annotations on Smith's website with key formulae, plus more extensive discussions of background information. Even without those, the book's first section ranges discursively through Napoleonic and post-revolutionary Russian history to introduce the frequencies and waves that Fourier used to describe the world, and the sampling theory of Kotelnikov and Shannon that explains how discrete digital bits like pixels can represent the visual world, where visual frequencies (not to be confused with light waves) are continuous and crammed with values. 

Wide ranging

Covering rockets and spies, Tom Stoppard plays and Alan Turing, von Neuman and vocoders, Smith ranges widely over the history of science and technology (and cinema). That's because he's not just exploring the background of display technology: he's also explaining information theory and a theory of his own. This is that significant developments in technology usually involve not just individuals with ideas that turn into breakthroughs, but also disruptive chaos that fuels the need for the breakthrough, plus a tyrant (anyone from Napoleon to Walt Disney) who deliberately or accidentally makes the space in which the breakthrough can happen (be that exile to a provincial town or providing funding and making demands). 

You don't have to be convinced by Smith's theory of history to find all this fascinating and informative. His theory of digital light is also something that's not commonly accepted, because no one has sat down and put together all the contributions and connections that go into how images are displayed on-screen (in terms of information rather than the physics of light). 

Pixels matter for a lot of computer graphics that there isn't room to cover in-depth in the book: digital photography, image processing, user interfaces, computer games, CAD, flight simulators, virtual and augmented reality. Smith draws some useful distinctions, like the difference between 'taking' and 'making' pixels, but as the book goes on, he concentrates more and more on the technologies that produced digital and especially computer-animated movies. 

Dense and extensively annotated, A Biography of the Pixel is both a fascinating account of 30 years of technology leading to the rise of digital film-making (and a century or so before that), and a reference book explaining how and why that technology works. The occasional flow charts that document the contributions of different people and projects to the development of cinema, the first computer systems or digital movies help you keep track of the wealth of detail. What counts as the very first computer? Who made the first moving picture, the first animated cartoon, the first colour pixels? (If you get lost in the book's scope, span and sheer detail, the closing section repeats all the key themes so you can see how they fit together.) 

History, with anecdotes

Anyone can explain computer graphics concepts like Bezier curves, motion blur, alpha channels and shaders: Smith tells the story of who came up with them and what problem they were trying to solve, along with anecdotes like the impossible camera viewpoint in the Klingon simulation of the Genesis Device in Star Trek II: The Wrath of Khan being there just to catch the attention of George Lucas. There's a lot of Pixar history along the way, because along with Ed Catmull and the other pioneers at Pixar, Smith was part of a lot of computer graphics 'firsts'. He even has some plausible theories about why Xerox PARC missed out on colour computing the way it did on personal computing, despite having so many experts and breakthroughs. 

Smith also tells the story of his own detective work, interviewing other computer graphics pioneers to trace the earlier history of the field, with lively anecdotes and personal accounts that reveal a lot of unsung heroes. 

No matter how much you already know about computer graphics, you'll find something new here, whether it's that the pixels you think you see when you zoom all the way into a digital image aren't really pixels, or the oil tanker simulation with computer-generated views of the New York City harbour, built in 1975 in a brick building that even looks like a ship. 

A Biography of the Pixel

$39.95 at MIT Press

As much history, genealogy and documentation as biography, this is an intriguing read that's really three or four books rolled into one. "My fervent intent is that you understand this piece of magic and be amazed by how it works," Smith says of pixels and digital light. You might be surprised by some of the twists and turns along the way, and you'll emerge with a much wider view of what goes into the digital media you look at next.

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