whatever face paint someone is wearing on a given day is/can be indicative of the following:

- clan (clan symbols are most commonly incorporated in some way or another)
- rank/squad (particularly in a military installation like this -- a soldier might be wearing certain colors/markings to denote a special task force or mission he is undertaking; this provides more nuanced information about a soldier at a glance than just the rank insignia on his uniform)
- occasion (for instance, formal occasions like the flower-viewing party would call for appropriate colors/designs)
- pursuit/occupation (on a base like this, it's more likely to denote a hobby than an occupation, but if someone is pursuing a particular artistic endeavor, that might be reflected in the design of their face paint)

it is complicated and nuanced, but wash is a smart guy and can probably have figured out some of this