 SPOILER: Although much of the films drama derives from the attempts  to enlarge a photo of a newspaper being held by a newsboy in the  street in order to see its date and thus determine the date the  photo was taken, in actuality this enlarging wasnt really necessary  at all. Since the layout of a newspapers front page changes daily,  and was visible in the photo without high magnification, even if  blurry, it would have been clear enough to disclose which days  issue it was when compared to archival copies, especially since it  was surmised what day it was, and what days newspaper was actually  seen, thus making the comparison very simple and straightforward.  The high technology enlarging process was a key dramatic sequence in  the film, but a concocted and unnecessary procedure, since the  question of the newspapers (and photos) date could have been  easily determined by direct and less dramatic low tech comparison.