[FJames]

The impression of text crispness on the display is a function of several things:

1. The actual screen resolution, which is 600 x 800 for the Pearl e-ink screen, or about 167 dpi. That's not as high as, say, the iPhone retina display at 326 dpi (2x linear or 4x area density).

2. The contrast ratio between black and white, which is only about 10:1 for a Pearl e-ink screen, compared to a typical backlit LCD display which manages about 500:1 in low ambient light, although it's not quite fair to compare the contrast ratio of a passive screen in high ambient light to a backlit screen in low ambient light. (Forget the high contrast ratios that you see for TVs - they are nothing more than a marketing fantasy.)

3. The font, i.e., the details, the density, whether anti-aliasing is used etc.. Many people have commented for example that the default Kindle font looks sharper than the default Kobo font on the same e-ink display, but it's primarily because it's a heavier font.

4. The screen refresh, just as the other posters have mentioned. The e-ink pixels often don't reset fully from black to white or white to black when re-written, leaving behind a faint ghost image of the previous contents. This builds up over several pages, leaving the impression of lower sharpness due to fainter black text and the faint gray image of past text on the white background. The flash-to-black full reset clears the display and returns it to pristine state.