The 'class' used for people who attend Amtgard on a given day but do not play a Battlegame. Colors are sometimes referred to as 'Blanket Bunnies'. Amtgarders playing as color may engage in; field side A&S, running events, providing beverages to ensure that none of the dehydrated idiots on the field die, calling the list for tourneys, acting as reeves, or willing handing out other essential help.
Colors are often, though not always, fighting the good fight to keep the game alive, with out thanks or reward; disdain them at your peril.
People who often sign in as color, but don't hand out help or add to the ambiance, are sometimes referred to Chair Farmers.