[geekmaster]

The Kindle pearl eInk screen contrast depends greatly on temperature, how long it has sat idle since the last screen refresh, and how many pages since a full flash update.

Because the new kindles do not do a full flash update on every page, comparing two identical kindles side-by-side will yield different results at different times.

The screen contrast is much better when the displays are warm, because they contain dark oil-filled beads. The oil viscosity changes with temperature. The screens contain a temperature sensor, which is used by the display driver software to tune the screen refresh algorithm to compensate for temperature differences. The beads also contain zinc oxide powder, which is attracted to the top or bottom surface of the screen with an electrical charge, with controlling waveforms that must be adjusted in both period and magnitude to maximize contrast.

The only realistic method to compare two units is to let them sit together awhile to equalize temperatures, then to exercise the screens by viewing multiple pages, then go to the page to compare and force multiple screen full flash updates. This can be done in a number of ways, such as taking a screen snapshot, or selecting and deselecting the menu.

Any other conclusion from comparing two units is a silly waste of nonsense.