One of the first things to check when dating Australian movie posters is the censorship details. They can often give a clue as to whether a poster is original or a re release. In the case of Doctor Zhivago, the film was released in 1965 so the censorship rating should be “Not Suitable for Children”. The poster on the left carries that rating and is the original daybill for that film. The other three daybills all display an NRC (Not Recommended for Children) rating so that indicates that they must have been released in the 70s.
The big question is why were the reissue daybills printed in three different colours. That is probably something we will never know but it is not uncommon amongst Australian posters. The Blue and Orange versions were printed by Robert Burton and the yellow style by M.A.P.S. Some collectors like to think that one version of the three may have come before another but it is most likely that the printers simply chose to use different colours for the re release posters.
This is one example of the reissue daybill being superior to the very ordinary artwork on the original.