Apple ColorLaserWriter 12/600PS - Manual (Page 46)

3 Turn gently until the carousel locks into a new position.
As you rotate the carousel through all four positions, the tab colors cycle from
magenta (pink) to cyan (blue) to yellow to black.
Cartridge carousel cycle
Yellow
Cyan
Magenta
Black
Notice that the color of
the tabs has changed.
21 Setting Up the Color LaserWriter 12/600 PS