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Amazon Kindle Paperwhite electronic book (e-book) reader

Electronic books

by Chris Woodford. Last updated: May 5, 2014.

Back in the 19th century English author, Martin Tupper wrote: "A good book is the best of friends, the same today and for ever." It's true: books are friendly, familiar, and loveable and that probably explains why it's taking us so long to get used to the idea of portable electronic books. But with the arrival of a new generation of electronic book readers, such as the Sony Reader, and Amazon Kindle, the days of the printed word just might be numbered. Let's take a closer look at electronic books (e-books) and find out how they work!

Photo: Left: Amazon Kindle Paperwhite electronic book reader. Right: The rival Sony Reader PRS-350 is considerably smaller and designed to carry around in your pocket. Both are smaller than the first generation of Kindles, because their touch-sensitive screens do away with the need for a separate keyboard.

Sony PRS 350 ebook reader

Two in one: books... and the information they contain

Think of a book and you think of a single object, but the books we read are actually two things in one: there's the information (the words and pictures and their meaning) and there's the physical object (the paper, cardboard, and ink) that contains them. Sometimes the physical part of a book is as important as the information it carries: it's really true that we judge books by their covers—at least when we're standing in shops deciding which ones to buy—and that's why publishers devote so much attention to making their books look attractive. But, a lot of the time, the information is much more important to us and we don't really care how it's delivered. That's why many of us now turn to the Web when we want to find things out instead of visiting the local library.

In short, we've learned to split off the information we need from the way it's delivered. E-books take this idea a step further. When we talk about an e-book, we really mean a digital version of a printed text that we can read on a handheld electronic device like a miniature laptop computer— two quite separate things, once again.

How do you store a book in electronic form?

An e-book is really just a computer file full of words (and sometimes images). In theory, you could make an e-book just by typing information into a word processor. The file you save has all the elements of an electronic book: you can read the information on a computer, search it for keywords, or share it easily with someone else.

The first attempt to create a worldwide library of e-books was called Project Gutenberg and it's still running today. Long before the World Wide Web came along, a bunch of dedicated Gutenberg volunteers took printed books and scanned or typed them into their computers to make electronic files they could share. For legal reasons, these books were (and still are) mostly classic old volumes that had fallen out of copyright. The electronic versions of these printed books are very basic, text-only computer files stored in a format called ASCII (American Standard Code for Information Interchange)—a way of representing letters, numbers, and symbols with the numbers 0-255 that virtually every computer can understand.

Amazon Kindle Paperwhite electronic book (e-book) reader side by side with Sony Reader

Photo: The Amazon Kindle Paperwhite electronic book reader (left) alongside the rival Sony eReader (right). This Kindle has a fairly unobtrusive set of LED lights built around the screen to make reading easier in the dim evening light. Although it's hard to see in this photo, the Paperwhite does has a much whiter, crisper screen than the Sony.

The problem with ASCII is that the text contains very little formatting information: you can't distinguish headings from text, there's only one basic font, and there's no bold or italics. That's why people developed much more sophisticated electronic files like PDF (Portable Document Format). The basic idea of PDF was to store an almost exact replica of a printed document in an electronic file that people could easily read on screens or print out, if they preferred. The HTML files people use to create web pages are another kind of electronic information. Every HTML page on a website is a bit like a separate page in a book, but the links on web pages mean you can easily hop around until you find exactly the information you want. The links on websites give you powerfully interconnected information that is often much quicker to use than a library of printed books.

The greatest strength of ASCII, PDF, and HTML files (you can read them on any computer) is also their greatest weakness: who wants to sit staring at a computer screen, reading thousands of words? Most screens are much less sharp than the type in a printed book and it quickly tires your eyes reading in this way. Even if you can store lots of books on your computer, you can't really take it to bed with you or read it on the beach or in the bath-tub! Now, there's nothing to stop you downloading simple text files onto something like an iPod or a cellphone and reading them, very slowly and painfully, from the small LCD display—but it's not most people's idea of curling up with a good book. What we really need is something with the power of a computer, the portability of a cellphone, and the friendliness and readability of a printed book. And that's exactly where electronic book readers come in.

How do you read an electronic book file?

An electronic book reader is a small, portable computer designed for reading books stored in a digital format such as ASCII, PDF, HTML, or another similar format. (Currently the two most popular ebook formats are EPUB, a worldwide, open standard that evolved from an earlier standard called OEB (Open e-book) and widely used by Sony Readers and most other ebook readers, and AZW, a proprietary format developed by Amazon and currently readable only on its Kindle reader.) Books take up very little space when you store them in electronic format: you could easily fit 10,000 electronic copies of the Bible onto a single DVD. Most ebook readers can store hundreds or even thousands of titles at a time and some have Wi-Fi Internet connections so you can download more books whenever you wish.

Screenshot of Caliber ebook.

The most important part of an e-book reader is the screen. The first e-books used small versions of LCD laptop screens which have a resolution (sharpness) of about 35 pixels per cm (90 pixels per inch). You could easily see the dots making up the letters and it was quite tiring to read for more than a few minutes at a time. The latest e-books use an entirely different technology called electronic ink. Instead of using LCD displays, they show words and letters using tiny, black and white plastic granules that move about inside microscopic, spherical capsules under precise electronic control. Displays like this have about twice the resolution of ordinary computer screens, are clearly visible in sunlight, and use much less power. In fact, they're almost as sharp and easy to read as printed paper. We'll see how these screens work in a moment.

The lack of books in electronic format is one of the things that puts people off using e-book readers—and that's what made Amazon.com's Kindle reader both an exciting development and an instant success. Amazon already worked with virtually all the world's publishers as a bookseller, so it was able to make huge numbers of titles available for Kindle in electronic format—over 88,000 books were available on the launch date. That's certainly what people want and expect from an e-book reader, but whether it will finally make electronic books as popular as iPods remains to be seen.

Photo: You can read electronic books right now, even if you don't have a handheld ebook reader. There's free electronic book software available for all the popular operating systems. You can also download versions of the Amazon Kindle that work on a PC, Mac, iPad, or cellphone. Here's an electronic book reader running on a normal computer screen, showing the first page of F.Scott Fitzgerald's The Beautiful and Damned.

How does E Ink® work?

Since electronic ink has been crucial to the success of ebooks, let's now take a detailed look at how it works.

Screenshot of an early pixelated space invaders arcade game.

You're probably reading these words in the same way that I am—by staring at a flat, LCD computer screen. For people over the age of about 35, who grew up with computers that used blocky green and black screens with just 40 characters across and 25 down, modern screens are wonderful and amazing. But they still have their drawbacks. Look closely, and you can see jagged edges to the letters. Try to read an LCD screen in direct sunlight and (unless the screen has a very bright backlight), you'll really struggle. But the worse thing is that LCD screens lack the lightness, portability, and sheer user-friendliness of ink-printed paper: you can happily read a book for hours, but try the same trick with a computer screen and your eyes will quickly tire.

Photo: Computer screens as we knew them in the late 1970s and early 1980s. At that time, the best screens could display no more than about 64,000 pixels and often just uppercase text or very crude "pixelated" (square block) graphics. Computer games like Space Invaders, shown here, were very primitive—but still highly addictive!

A comparison of a word printed on an LCD and an E Ink display

Back in the early 1970s, the Xerox Corporation that had pioneered photocopiers a decade earlier became concerned about the threat that computers might pose to its core ink-and-paper business: if everyone started using computers, and offices became paperless, what would happen to a company so utterly dependent on paper technology? It was for that reason that Xerox pumped huge amounts of money into PARC™, (Palto Alto Research Center), the now-legendary campus where modern, user-friendly personal computing was pioneered. Among the many innovations developed there were personal computers that used a graphical user interface (the "desktop" screen featuring icons, later copied by the Apple Macintosh® and Microsoft Windows®), Ethernet networking, laser printers... and electronic paper, which was invented by PARC researcher Nick Sheridon.

The basic idea of electronic ink and paper was (and remains) very simple: to produce an electronic display with all the control and convenience of a computer screen but the readability, portability, and user-friendliness of paper.

Photo: The E Ink® display on a Sony Reader (bottom) is much sharper and easier to read than a typical LCD screen (top). Magnifying by about 8–10 times and zooming in on a single word, you can see why. The E Ink display makes sharper letters with a uniformly white background. The LCD display blurs its letters with anti-aliasing to make them less jagged, though that makes them harder to read close up. The red, blue, and green colored pixels used to make up the LCD's "white" background are also much more noticeable. Unlike the E Ink display, an LCD does not use a true white background: it relies on your eye and brain to fuse colored pixels instead. The resolution of E Ink is also far greater: typical LCD displays use around 90 pixels per inch, whereas E Ink displays use at least twice as many pixels.

How does electronic ink and paper work?

A simple animation showing how electronic ink works through electrophoresis: black and white ink capsules move under the control of an electric field.

Most electronic ink and paper screens use a technology called electrophoresis, which sounds complex but simply means using electricity to move tiny particles (in this case ink) through a fluid (in this case a liquid or gel). Other uses of electrophoresis include DNA testing, where electricity is used to separate the parts of a DNA sample by making them move across a gel, which enables them to be compared with other samples and identified.

In one of the best-known electronic ink products, called E Ink® and used in ebooks such as the Amazon Kindle, there are millions of microcapsules, roughly the same diameter as a human hair, each of which is the equivalent of a single pixel (one of the tiny squares or rectangles from which the picture on a computer or TV screen is built up). Each capsule is filled with a clear fluid and contains two kinds of tiny ink granules: white ones (which are positively charged) and black ones (which are negatively charged). The capsules are suspended between electrodes switched on and off by an electronic circuit, and each one can be controlled individually. By changing the electric field between the electrodes, it's possible to make the white or black granules move to the top of a capsule (the part closest to the reader's eye) so it appears like a white or black pixel. By controlling large numbers of pixels in this way, it's possible to display text or pictures.

Animation: Electronic ink works through electrophoresis. Each pixel (microcapsule) in the display (the gray circle) contains black (negatively charged) and white (positively charged) ink granules. When a positive field (shown in blue) is applied to the top electrode, the black capsules migrate to the top, making the pixel look black when seen from above; switching the field over makes the granules change position so the pixel appears white.

Advantages and disadvantages of electronic ink

If you've tried reading an electronic book, you'll know that electronic ink and paper is much easier to read from for long periods than an LCD computer screen. Since the microcapsules stay in position indefinitely, with little or no electric current, electronic ink displays have extremely low power consumption. A typical ebook reader with an E Ink display can be used for something like 2–4 weeks of average everyday reading on a single charge. Low power consumption means low energy use and that translates into an environmental benefit; in other words, electronic ink and paper is environmentally friendly.

The disadvantages are less obvious until you start using electronic ink in earnest. First, although the displays work excellently in bright indoor light and daylight, including direct sunlight, they have no light of their own (unlike LCD displays, which have backlights shining through them from back to front so you can see them). That makes them hard to use in poor indoor light, especially in the evenings, which is why many ebook readers are sold with clumsy addon lamps. Electronic ink also takes much longer to build up the image of a page than an LCD screen, which means it's unsuitable for everyday computer displays using any kind of moving image (and completely unsuitable for fast-moving images such as computer games and videos). Sometimes parts of a previous page linger on as "ghosts" until you've turned another page or two. You've probably noticed that, when you "turn the page" of an electronic book, the entire screen momentarily flashes black before the new page is displayed? That's a rather clumsy compromise to prevent ghosts, in which the screen tries to erase the previous page before displaying a new one (a bit like Etch-a-Sketch®!).

Another major disadvantage is that most electronic ink displays are currently black and white. Color displays do exist (E Ink produces one called Triton, in which a layer of red, green, and blue color filters is mounted over the usual black-and-white microcapsules) and better ones are in development, but they're much more expensive than their black-and-white electronic paper (or LCD equivalents). In time, we're bound to have color electronic books and magazines; according to Amazon's Jeff Bezos, however, speaking in mid-2009, a color Kindle ebook reader is "multiple years" away: "I've seen the color displays in the laboratory and I can assure you they're not ready for prime time." (Amazon's color Kindle Fire™ product, announced in September 2011, uses an LCD display.)

A comparison of an E Ink ebook display and an LCD screen in bright sunlight A comparison of an E Ink ebook display and an LCD screen in dark, indoor evening light

Photo: Night and day, are you the one? Here I've propped a Sony Reader against the screen of a conventional laptop and photographed it in different light conditions. Left: In bright light or daytime outdoors, electronic ink displays are much easier to read than backlit LCD displays, which become virtually invisible. Right: In dark indoor light in the evenings, things are reversed: LCDs are much easier to read and electronic ink displays are a struggle to decipher unless you sit in strong light (or use a clip-on light attachment).

Which electronic book reader should I buy?

A Sony Reader laid on a hardback book to show the difference in page size

Kindle, Sony Reader, Nook, Elonex—which one should you buy?

They're all broadly similar: they're all light, portable, and handheld and they all have large internal flash memories that hold hundreds or thousands of books. Some have touchscreens; others (like the older ande cheaper Kindles) have miniature keyboards. Some have wireless connections for downloading more books; others (such as the Sony Readers) have to be connected to a computer with a USB cable. If you connect with USB, running an ebook reader is rather like running an iPod or MP3 player: typically you maintain a library on your PC with a piece of software similar to iTunes, to which you add and remove books and other documents. When you plug in your reader, it synchronizes its internal memory with the library on your PC, adding any new books and deleting any unwanted ones. If you have a wireless reader, you maintain your library on the reader itself or in the cloud (stored on a remote computer somewhere and accessed online), adding and removing books directly. So... wireless or cable? It's not a big issue, I don't think.

Photo: Horses for courses: Portable versions of the Sony Reader have a much smaller page size than a typical hardbook book. That's great if you want to carry your reader in your jacket pocket or your handbag so you can read while you're travelling. It's much less attractive if you do most of your reading at home: the smaller the screen, the more often you'll need to turn the pages. This is one example of why it pays to think about how you're going to use an ebook reader before you buy it.

Displays and batteries

The best and most expensive readers use extremely high-resolution E Ink screens that work better in daylight than at night (you'll need good indoor lighting or a clip-on light if you're planning to do most of your e-reading in the evenings); LCD-screen readers (such as the Elonex) have backlit screens that favor indoor use and (like computer screens) can be tricky to read in bright sunlight. Amazon's current state-of-the-art reader, the Kindle Paperwhite, has discreet little LED lights built around the edge of the screen that make a noticeable difference when you're reading indoors in the dim evening light.

E Ink apparently uses energy only when you turn the pages, so the Sony Reader can happily survive for about two weeks of very heavy use on a single charge of the batteries, while the Kindle Paperwhite claims up to eight weeks of battery time. That means it's also very environmentally friendly to read books or documents from a handheld ebook reader compared to reading them on a computer screen.

Some ebook readers can cope with ebooks in all kinds of different formats. The Sony Reader, for example, lets you read Microsoft Word and PDF files, as well as standard formats such as EPUB. The PDF viewer is really neat, allowing you to rotate the screen or scroll documents column-by-column for easy reading. The Amazon Kindle doesn't currently support the EPUB format, but it does allow you to view other file formats such as PDF. You can also mail documents to your Kindle, which is something you can't do on a Sony.

A Sony Reader turned into landscape format to read a PDF file

Photo: You can use the Sony Reader in "landscape" orientation if you find that easier, though you have to switch it over manually from the keyboard (unlike with a smartphone, the display doesn't rotate itself). Here I'm reading a PDF file of Sustainable Energy—Without the hot air by physicist David MacKay. If environmental issues matter to you, reading documents on an ebook reader like this might appeal, because it uses a fraction as much energy as a laptop. The text is much more legible than it appears in this photograph.

Where can you get ebooks from?

Most books currently produced by publishers are copyrighted, which means you can expect to pay a fair price if you want to use them. Relatively few publishers have embraced ebooks so far, though there are some notable exceptions (including Penguin). Generally, it's relatively easy to find mass-market bestsellers in ebook format but much harder to find more specialized books and quality, literary fiction. Public domain classics are the easiest books to find in ebook format, largely thanks to the sterling and visionary work of Project Gutenberg. If you enjoy reading classic novels, buying an ebook reader is probably a no-brainer; if you're more a fan of 20th century literary fiction, you'll have a much harder time finding what you want in digital form.

If you buy copyright ebooks from either Amazon or another outlet, you'll find they're protected by what's called DRM (digital rights management)—effectively a kind of encryption that prevents people from distributing pirate copies of books illegally. Amazon uses its own DRM system, while Sony (and others) use a system developed by Adobe called Adobe Digital Editions, which requires you to register your reader the first time you use it. DRM protection restricts what you can do with books you've bought, but it's not necessarily the drawback it seems. First, it's very much a necessity from a publisher's point of view: it's only because ebook readers like the Kindle have DRM protection built in that publishers are starting to take what they see as a major risk in making their books available in digital formats. Another advantage of DRM is that it allows libraries to lend people ebooks for limited periods of time. I'm delighted to find I can log in to my local library and download, for free, for periods of up to 14 days, a fair selection of a few hundred popular ebooks. Once the borrowing time has expired, the books delete themselves automatically from my reader!

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Text copyright © Chris Woodford 2008, 2014. All rights reserved. Full copyright notice and terms of use.

E Ink is a registered trademark of E Ink Corporation.

Kindle and Paperwhite are trademarks of Amazon.com, Inc or its associated companies.

NOOK is a trademark of Barnes and Noble.

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Woodford, Chris. (2008/2011) Ebooks. Retrieved from http://www.explainthatstuff.com/ebooks.html. [Accessed (Insert date here)]

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