Usually three or four such rollers are required to ink the forme.
It is then brought under the second or left-hand drum, and so on to the other large impression cylinder, with the blank side of the sheet exposed to the type of the outer forme on the table underneath.
Now, supposing the forme to be dealt with consists of thirty-two pages to be printed on quad crown paper, measuring 40X30 in., on a suitable size of single cylinder machine of the Wharfedale class, it would be found, although both the machine and type were fairly new (that is, not much worn), that there was some amount of inequality in the impression given to the whole sheet.
It may even be necessary for fine printing to repeat this a third time, especially if the forme includes blocks of any kind.
If the forme to be printed consists of both type and blocks mixed, a somewhat different treatment has to he employed in order to put the blocks into a relative position with the type for printing.