Here's another example, notable in the way the color drains away as the scene switches from greenery to man-made interiors:
There are even a few chapters that end with color pages, and they pull the same trick, in reverse:
This is something that I've never seen any other manga (or Western comic, although it's not as likely to be an issue there) do. It's an interesting idea, and one that could stand to be explored. Masamune Shirow; he was kind of ahead of his time, wasn't he?