Incidentally, they also have an optional but suggested charge for papers containing color diagrams and over-length papers. These are wonderful holdovers from w

Incidentally, they also have an optional but suggested charge for papers containing color diagrams and over-length papers. These are wonderful holdovers from when people read papers in actual printed copies. When's the last time you read a paper from a printed copy from the publisher? That's why they're "optional" (and roundly ignored, AFAIK). It's another example of their completely outdated monetization methods.