Ghost Image

[steve B]

The colors were probably done one at a time.*
The diagram Treyboo posted is a great one, it covers the main idea, while not confusing with the extra rollers above that.
T206s were printed on a slightly different press, a flatbed offset press, where the "plate" was an actual stone, a large flat piece of limestone.
But that diagram still works for the concept. (the flatbed offset presses are a bit crazy mechanically. )

Typically, you'd want to do the lightest color first, darkest last.

In modern stuff where it's just yellow, blue, red, black they usually get done in that order.
T206s were a minimum of six colors, and usually more like 8 sometimes more.
Logically, they should be done the same way, and they usually are. Light blue is under dark blue, pink under bright red etc.
But there is a group that is different, the ones showing only yellow and brown.
I suspect brown was done just after yellow to give a nice solid color to compare registration of the later colors to since yellow can be hard to see.

* Now we get to the neat conjecture portion !
Around 1910, some of the first multi color lithographic presses were being made. (Picture two presses connected, and the paper goes directly from one to the other without any handling etc. ) One of the pioneering companies appears to have been a favorite supplier to ALC.
There are the yellow/browns, and many of the missing color cards aren't just missing one color. That leads me to believe that at least parts of some runs were done on a two color press.