Fuji Xerox has developed a color e-paper that does not need a color filter. Color, is typically achieved on an e-reader by putting a filter over the black and white display, which results in washed out tones.
The Fuji Xerox prototype is not like that. It works by moving around the particles that make up each color, and every one of these particles has a different charge, making it possible for each one to be controlled.
The paper will comprise of two panels and you're able to see a certain color when its associated particle is brought to the front. While its just a prototype, it makes the future of an e-reader more exciting.
Here's hoping the commercially available version will be a tad bit better.