6th Definitive Series - Colour - Marginal Markings

What are plate markings?
Plate markings made when the stamps are printed include guide lines, arrows, registration marks for stamps in two or more colors. Electronic eye marks, designs, initials, imprints of manufacturers' names' plate numbers, stars from some United States plates are among the numerous types of inscription printed in marginal paper. Plates markings should not be confused with hand-stamped markings in the marginal paper. Hand-stamped markings are not in the samecolors as the postage stamps they identify.