IS0 26:1993 pdf download – Cinematography – Projector usage of 16 mm motion-picture films for direct front projection – Specificät ions.
1 Scope This International Standard specifies the emulsion orientation, the rate of projection, the position of the projected image area and the relationship between picture and sound in the projector, intended for direct front projection of 16 mm motion-picture films with photographic and magnetic sound records and 16 mm silent motion-picture films. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publi- cation, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most re- cent editions of the standards indicated below. Members of IEC and IS0 maintain registers of cur- rently valid International Standards. I S0 490:-”, Cinematography – Magnetic stripes and magnetic recording head gaps for sound record on 16 mm motion-picture film perforated along one edge (Type I) – Positions and width dimensions. I S0 4243:1979, Cinematography – Picture image area and photographic sound record on 16 mm motion-picture release prints – Positions and dimen- sions. 3 Emulsion orientation For 1 6 mm film, the emulsion position is dependent on the process of preparation and either emulsion-to- light source or emulsion-to-objective lens orientation can be encountered. The actual emulsion position should be indicated by a clear statement or diagram on the leader and on the label of the film container as recommended in IS0 5768 and I S0 8400. 4 Rate of projection The rate of projection shall be 1 8 frames per second f 1 frame per second (preferred) or 16 frames per second $1; frames per second for silent motion- picture films and 24 frames per second f 1 frame per second for sound motion-picture films. NOTES 1 Silent projectors having manually adjustable speed should be capable of reaching projection rates of 1 6 and 1 8 frames per second. 2 When a sound film is used in television in areas where the mains electricity supply is a.c. at 50 Hz, a rate of pro- jection of 25 frames per second applies. 5 Position of projected image area The projected image area shall be located in the ver- tical direction so that the horizontal axis of the pro- jected area passes through the middle of the distance between the film perforations, as shown in figure1 (dimension A). It is recommended that projectors be provided with a framing adjustment of 0,5 mm (0,020 in) minimum above and below the nominal position. 6 Relationship between picture and sound record in the projector The sound record as located in the film path of the projector shall precede the centre of the correspond- ing picture by the distances specified in I S0 490 and IS0 4243.