' The problem - and I have asked people who have forgotten more about postcards than I will ever know - is the meaning of the word "hand".
Some cards were colored one-by-one by hand, in the sense that some guy (most often a one-armed WW1 vet) would swipe a brush over the card.
Some cards were colored by once/more runs thru a press, each time adding some tint here or there.
Now go tell these apart.
I have yet to meet anyone who thinks that publishers were especially careful in their use of terms like "hand-colored" to mean only one of these, or that it is always easy/possible to distinguish one process for another if you only have one copy of that card at-hand.
Even a consistent color shift - eg, the orangey color that was meant to suggest light streaming out of windows on a building - means little, as the one-by-one guy could/would have been using a mask.