Cement splicers join films together by using a chemical called
film cement which is made of film base dissolved in a solvent. The
photographic emulsion is removed from the area to be joined and the base of the other end is brought into contact with it. Film editors use a version with a very small overlaps at the top and bottom of the picture frame to edit film
negatives, although units with a longer overlap are preferred for projection
release prints. These can only be used with
acetate,
triacetate and
nitrate films. Polyester film, such as that used for currently produced prints, will not bond with standard film cement. ==Tape splicers==