What’s difference between hanging plating and rolling plating?

Metal accessories always with color plating, most of them will apply hanging plating and rolling plating.
Do you know what’ s difference between them?

Hanging plating:

Each items hanged up to be colored.
Hanging plating make the color more even and shining, with higher price, available fore middle to high end market

Rolling Plating:

All items bath in a big barrel to be colored.
Rolling plating make the color more with lower price, available fore middle to low end market