What Makes a Poster Original?
Authentic vintage movie posters were printed for theatrical use — not for sale to collectors. This means they were produced on cheaper paper, often with imperfect registration, and were meant to be displayed and discarded. Those characteristics are now the very things that authenticate them.
Paper Stock
Original one-sheets from the studio era (1930s–1960s) were printed on a lightweight, slightly absorbent paper stock. Hold the poster up to light — you should see a slightly uneven texture and occasional small fibres in the paper. Reproductions are almost always printed on a heavier, coated stock that feels slick.
Printing Techniques
Before offset lithography became standard, most posters were stone litho or letter-press printed. Look for slight ink relief on the surface, and colours that are made up of halftone dots when viewed under magnification.