““‘But in, you know, the Muggle world, people just stay put in photos.’
‘Do they. What, they don’t move at all?’ Ron sounded amazed. ‘Weird!’
Harry stared as Dumbledore sidled back into the picture on his card and gave him a small smile” 
Current Uses of Electronic Ink
Electronic ink can now be found daily in various technologies. It has been used in the screens and keypads of mobile phones such as the Motorola F3 and Samsung Alias 2. It can be seen in various signs, billboards, and retail store pricing labels . The most well-known current use of electronic ink, however, is in the screens of e-readers like the Amazon Kindle or Barnes & Noble Nook (Fig. 1). Amazon has sold an estimated 3 million Kindles, first released in 2007, demonstrating the commercial success of electronic ink .
How Does Electronic Ink Work?
Electrophoretic ink takes advantage of different colored, oppositely charged particles moving into view to form patterns. Electrophoresis separates particles by their charge by applying voltage via electrodes; positively charged molecules are attracted to negative voltages, and negatively charged molecules are attracted to positive voltages.The ink itself consists of countless solid microcapsules that have three main components (Fig. 2) :
• Negatively charged black particles
• Positively charged white particles
• Transparent liquid
Making the Ink
Printing the Ink and Making It Write
Adding Color to the Ink
In late 2010, E-Ink announced that it had achieved color capability in its electronic paper displays through the addition of a color filter . This filter, placed between the ink microcapsules and the transparent screen, has red, green, and blue components to create a full range of colors (Fig. 4). The desired colors are produced by arranging the microcapsules in appropriate patterns as directed by processors.
Use of Electronic Ink Displays Versus Traditional LCD Screens
Sustainability of Electronic Ink
Reading Into the Future of Electronic Ink
Electronic ink makers are taking several approaches to meet these goals. Some seek to improve upon existing electrophoretic ink technology. Others focus on developing newer types of electronic ink that have demonstrated potential. Like electrophoretic ink, these other inks imitate the appearance of ordinary ink on paper, but through different mechanisms. Electrowetting technology, for example, applies voltage to control the shape of an oil-water interface, which moves quickly allowing for a high refresh rate. Electrofluidic technology uses electricity to control the movement of liquids through tiny cavities, producing vivid colors and highly reflective screens. Cholesteric liquid crystals use stable liquid crystals that reflect light and can be made into thin and flexible sheets . These different types of electronic ink have yet to be released on the market but have great potential for future applications in all kinds of displays and screens (Fig. 5).
-  J. K. Rowling. Harry Potter and the Sorcerer’s Stone, A.A. Levine, New York, 1998, pp. 82.
-  Ford Motor Company. “Esquire becomes first magazine to merge digital
- technology with printed pages.” Internet: http://media.ford.com/article_display.cfm? article_id=28680, July 21, 2008 [June 22, 2011].
-  A. A. Terry. Electronic Ink Technologies: Showing the Way to a Better Future. Library Hi-Tech 19.4, 2001, pp. 376-89.
-  Epapercentral.com. “E-paper Technologies Reference Guide.” Internet: http://www.epapercentral.com/epaper-technologies-guide, [June 22, 2011].
-  M. Arrington. (2010, Jan.). “3 Million Amazon Kindles Sold, Apparently.” TechCrunch. Internet: http://techcrunch.com/2010/01/29/3-million-amazon-kindles-sold-apparently [June 22, 2011].
-  J. Stricklan. “How the Amazon Kindle Works.” Internet: http://electronics.howstuffworks.com/gadgets/travel/amazon-kindle1.htm, [June 22, 2011].
-  Epapercentral.com. “Can E Ink Hold Up to Other Upcoming E-Paper Technologies?” Internet: http://www.epapercentral.com/can-eink-hold-up-to-other-upcoming-epaper-technologies.htm, [June 22, 2011].
-  T. Carmody. (2010, Nov.). “How E Ink’s Triton Color Displays Work, In E-Readers and Beyond.” Wired. Internet: http://www.wired.com/gadgetlab/2010/11/how-e-inks-triton-color-displays-work-in-e-readers-and-beyond [June 22, 2011].
-  D. Carnoy. “LCD vs. E-ink: The Eyestrain Debate.” Internet: http://reviews.cnet.com/8301-18438_7-20021227-82.html, Oct. 29, 2010 [June 22, 2011].
-  M. Starr. “What to Look for in an E-reader – Tablets & E-readers Computers.” Internet: http://www.cnet.com.au/what-to-look-for-in-an-e-reader-339316831.htm.
-  P. Ganapati. (2010, Feb.). “5 Things That Will Make E-Readers Better in 2010.” Wired. Internet: http://www.wired.com/gadgetlab/2010/02/e-readers-innovations-2010 [June 22, 2011].
-  (2009, July). “New Generation of E-Book Readers Contributes to Environmental Protection.” Dbreaders/i]. Internet: http://www.digital-book-readers.com/new-generation-of-e-book-readers-contributes-to-environmental-protection [June 22, 2011].
-  G. Kozak. 2003. Printed Scholarly Books and E-book Reading Devices: A Comparative Life Cycle Assessment of Two Book Options. Master’s Thesis, University of Michigan, Ann Arbor, pp. 83-85.
-  V. Song. (2009, Jan.). “Electronic Ink: Paperless Display Technology Saves Trees and the Environment.” Toronto Sun. Internet: http://www.torontosun.com/life/greenplanet/2009/01/17/8054911-sun.html [June 22, 2011].
-  N. Deleon. (2010, Aug.). “Hands-On First Impressions: Amazon Kindle 3.” CrunchGear. Web. 24 June 2011. Internet: http://www.crunchgear.com/2010/08/25/k, Aug. 25, 2010 [June 24, 2011].