In other words, each individual frame you are taking is somewhere in-between 2K and 4K res, but for coloring and cleanup work you are using a downsample because that will be faster and yield similar results to doing all your editing at the higher (let's call it 3K) resolution, only to have to size it down anyway at the end, for home video.
EDIT: Oh, I see. So you really did do a real 4K transfer of this print?