Perforations

Some articles on perforations, perforation:

Aspect Ratio (image) - Practical Limitations
... the physical size of the film area between the sprocket perforations determines the image's size ... (established by William Dickson and Thomas Edison in 1892) is a frame that is four perforations high ... film itself is 35 mm wide (1.38 in), but the area between the perforations is 24.89 mm×18.67 mm (0.980 in×0.735 in), leaving the de facto ratio of 43, or 1.331 ...
Velology - History of Tax Discs
... Early discs were made from plain paper, without perforations the selvedge was cut or folded to create the main circular shape ... Perforations were used from 1938, enabling a better fit within the standard disc holders however, the perforations were missing from 1942 to 1952, perhaps as a result of equipment ...
Large Hermes Head - Perforations
... However unofficial perforations were produced locally ... The most commonly found is the so-called Athens perforation (11½) ...
Film Perforations
... Film perforations, also known as perfs, are the holes placed in the film stock during manufacturing and used for transporting (by sprockets and claws) and steadying (by pin ... Films may have different types of perforations depending on film gauge, film format, and the intended usage ... Perforations are also used as a standard measuring reference within certain camera systems to refer to the size of the frame ...
Continuous Stationery - Common Types
... It uses a very fine perforation of tiny pinholes, and is pre-scored along the perforations ... The fine row of perforations tear off as a very smooth edge that simulates the edge quality of normal cut-sheet typing paper, without the jagged appearance of cheaper long-slit perforations ...