When the register marks corresponding to these colour forms have also been cut, and the paper washed off the blocks, the clear spaces may be used for pasting down new key impressions for the smaller colour patches and their corresponding register marks. In this way one side of a colour plank may contain several different colour forms and sets of register marks. As a rule the different colour patches would be printed separately, though in some cases two colours may be printed at one impression if they are small and have the same register marks.
