Kindle Optimizer

What is the Kindle, and why should you care what I think about it?

The Kindle is Amazon's e-book reading device. While there have been other readers, Amazon's device breaks new ground. It is attractive, full featured, and provides full-time wireless connectivity for a read-anywhere, buy-anytime experience.

You likely know all this already. There are plenty of reviews of the Kindle. You're probably here because you already own a Kindle and you'd like to know how to optimize your "reading experience." That's what this site is about.

What's up with all the fonts?

The Kindle is an amazing device. But it can be improved. Some of the hottest topics on the Kindle discussion boards revolve around the display. This makes sense because the Kindle is all about the display. It's a reading device!

When you deconstruct things, the display comes down to the readability of the fonts. This is where I come in.

While reading the discussion groups, I found people complaining about the contrast of the Kindle's display and the readability of the text. People were quite passionate about this topic. It seemed everybody loved the concept of the Kindle, but they were having problems with eye-strain unless they used larger font sizes.

Not everybody complained, and perhaps it was just a vocal minority. But they existed. People were returning devices in hopes of getting one with a better screen. Something was clearly wrong!

I spent about 20 years of my life helping to advance the state-of-the-art in digital imaging, so contrast and pixels are my lifeblood. In addition, I like making good things better, it's called "optimization."

Back to fonts! So in my quest to optimize the Kindle, I started analyzing the Kindle's screen more closely. This image is extremely revealing.

Note that there are only several shades of pixels in the image. The background is "white", some pixels are "black" and there appear to be two other shades of intermediate gray pixels.

As you can see, the primary outline of the characters is not black. It's black in some areas and gray in others. Fonts are drawn in this way to make them appear smoother. And usually it works well. On  a conventional computer screen, this tricks the eye into seeing a smooth curve rather than coarse details rendered by individual pixels. This is referred to as anti-aliasing or font-smoothing.

If you Google on font-smoothing, you will find many more articles on this topic.

This takes you to a page where you can donate to the cause
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Why does font smoothing degrade the Kindle's display

On a normal computer screen, the image is composed of luminous pixels. The eye sees the background as "white", and pixels that are off are typically quite "black". The Kindle has a reflective screen. "Black' pixels, still reflect some light and the "white" pixels only reflect a certain fraction of the light (rated at 40% by the manufacturer). Hence the difference between black and white on a screen is vastly higher than on a Kindle. This is technically referred to as the contrast ratio. (See also this technical article.)

On a computer screen, this ratio might be 1000:1 or more. On the Kindle, it is 7:1 with the E-Ink display. This is a huge fundamental difference in potential contrast!

(For reference, newsprint has a contrast ratio of about 10:1 and a reflective LCD display is only about 5:1.)

So, from the start, the Kindle is fighting a lopsided battle. It is physically impossible for the Kindle display to render with as much contrast as a backlit LCD display.

That said, it is possible to make a good looking display with an E-Ink display as evidenced by many of the Kindle's displayed pages, especially at larger font sizes. In fact, one might say that the Kindle display is beautiful. And, the E-Ink display is right in the ballpark of other reflective displays and newsprint.
Note the smooth flowing lines and the fine details. The fonts are very aesthetically pleasing. But look closer. The smaller the font, the grayer. The characters start losing contrast. The magnified image shown earlier demonstrates exactly why this occurs. There simply aren't enough black pixels in the character - the font smoothing has broken down.
Now look at a blowup of a larger character. In this rendering, there are black pixels defining the entire boundary of the character while the gray pixels help smooth out the transitions. When viewed in its normal size, as shown above, it is perceived as a smooth character. This wonderfully illustrates the positive effects of font smoothing
So how can one achieve beautiful large fonts while retaining the clarity of smaller ones on the Kindle's limited display? That is what I set out to solve.

Side note on Kindle's implementation of Font Smoothing

For the techies or Amazon programmers. See this link.